Computer manufacturers are working hard on their answer to the iPad with models in various sizes and designs expected in the coming months.
Microsoft is leading the charge by working with numerous partners to develop small tablet computers running Windows 7. CEO Steve Ballmer has named Asus, Dell, Sony, Hewlett-Packard, and Lenovo by name, among others. This isn't Microsoft's first try in the tablet computer ring, either. The company's first models back in 2001 were primarily oriented toward business customers.
"It depends entirely on what you want to do with it," says Florian Muessig from German computer magazine c't when asked about the choice between a tablet computer and a netbook. The iPad is better for many computer games than a mini-laptop. Electronic books (eBooks) are also better suited for the tablet computer. The biggest advantage cited by the hardware expert is the fast bootup: 'You press the button and it's on.'
Netbooks have moved on in recent years beyond their original, limited intended purpose. At prices below $200 -- and thus significantly cheaper than an iPad (starting at $500) -- a netbook offers almost everything a modern PC can do, except with less processing power and lower resolution screens. The next generation will be coming with new double core Atom series processors from Intel. "But I'm not counting on seeing them this year," Muessig says.
With a battery life of up to ten hours, the iPad is built for the long haul, or long plane ride. Netbook batteries have typically maxed out at seven hours. Some of the new models are promising up to ten hours or more, though, and "for netbooks in particular battery life is a crucial factor," says Samsung manager Dirk Neuneier.
There are significant differences in the available storage memory. While netbooks usually have hard drives capable of holding 160 or 250 GB, the iPad holds only 16 to 64 GB. There's only one way to store more data than that: the internet. After all, the iPad has no USB port to insert external storage media. The tablet computers from other manufacturers hope to seize that niche.
"An iPad is used to communicate information quickly," explains Product Manager Joerg Wissing from netbook Pionier Asus. "If you want to work creatively, then a netbook is certainly a better choice."
The Taiwanese hardware maker wants to produce devices in both categories and is preparing tablet computers of various sizes. "We're in the development phase and are keeping our eyes and ears open about what users need," Wissing says. "The fast on and off is certainly a topic. A USB is planned, but the decision on the operating system is still open."
Software is getting more and more important. The iPad was a success not least because of its mobile operating system, now known as iOs, which harmonises perfectly with the hardware. Netbooks typically run on Windows.
Showing posts with label hardware. Show all posts
Showing posts with label hardware. Show all posts
Sunday, September 5, 2010
Thursday, April 1, 2010
Basics of computer hardware
Basics of computer hardware
A computer is a programmable machine (or more precisely, a programmable sequential state machine). There are two basic kinds of computers: analog and digital.
Analog computers are analog devices. That is, they have continuous states rather than discrete numbered states. An analog computer can represent fractional or irrational values exactly, with no round-off. Analog computers are almost never used outside of experimental settings.
A digital computer is a programmable clocked sequential state machine. A digital computer uses discrete states. A binary digital computer uses two discrete states, such as positive/negative, high/low, on/off, used to represent the binary digits zero and one.
The French word ordinateur, meaning that which puts things in order, is a good description of the most common functionality of computers.
Google
OSdata.com is used in more than 300 colleges and universities around the world
Find out how to get similar high web traffic and search engine placement.
what are computers used for?
Computers are used for a wide variety of purposes.
Data processing is commercial and financial work. This includes such things as billing, shipping and receiving, inventory control, and similar business related functions, as well as the “electronic office”.
Scientific processing is using a computer to support science. This can be as simple as gathering and analyzing raw data and as complex as modelling natural phenomenon (weather and climate models, thermodynamics, nuclear engineering, etc.).
Multimedia includes content creation (composing music, performing music, recording music, editing film and video, special effects, animation, illustration, laying out print materials, etc.) and multimedia playback (games, DVDs, instructional materials, etc.).
parts of a computer
The classic crude oversimplication of a computer is that it contains three elements: processor unit, memory, and I/O (input/output). The borders between those three terms are highly ambigious, non-contiguous, and erratically shifting.
hardware subsystems of a computer
A slightly less crude oversimplification divides a computer into five elements: arithmetic and logic subsystem, control subsystem, main storage, input subsystem, and output subsystem.
* processor
* arithmetic and logic
* control
* main storage
* external storage
* input/output overview
* input
* output
processor
The processor is the part of the computer that actually does the computations. This is sometimes called an MPU (for main processor unit) or CPU (for central processing unit or central processor unit).
A processor typically contains an arithmetic/logic unit (ALU), control unit (including processor flags, flag register, or status register), internal buses, and sometimes special function units (the most common special function unit being a floating point unit for floating point arithmetic).
Some computers have more than one processor. This is called multi-processing.
The major kinds of digital processors are: CISC, RISC, DSP, and hybrid.
CISC stands for Complex Instruction Set Computer. Mainframe computers and minicomputers were CISC processors, with manufacturers competing to offer the most useful instruction sets. Many of the first two generations of microprocessors were also CISC.
RISC stands for Reduced Instruction Set Computer. RISC came about as a result of academic research that showed that a small well designed instruction set running compiled programs at high speed could perform more computing work than a CISC running the same programs (although very expensive hand optimized assembly language favored CISC).
DSP stands for Digital Signal Processing. DSP is used primarily in dedicated devices, such as MODEMs, digital cameras, graphics cards, and other specialty devices.
Hybrid processors combine elements of two or three of the major classes of processors.
For more detailed information on these classes of processors, see processors.
arithmetic and logic
An arithmetic/logic unit (ALU) performs integer arithmetic and logic operations. It also performs shift and rotate operations and other specialized operations. Usually floating point arithmetic is performed by a dedicated floating point unit (FPU), which may be implemented as a co-processor.
An arithmetic/logic unit (ALU) performs integer arithmetic and logic operations. It also performs shift and rotate operations and other specialized operations. Usually floating point arithmetic is performed by a dedicated floating point unit (FPU), which may be implemented as a co-processor.
control
Control units are in charge of the computer. Control units fetch and decode machine instructions. Control units may also control some external devices.
A bus is a set (group) of parallel lines that information (data, addresses, instructions, and other information) travels on inside a computer. Information travels on buses as a series of electrical pulses, each pulse representing a one bit or a zero bit (there are trinary, or three-state, buses, but they are rare). An internal bus is a bus inside the processor, moving data, addresses, instructions, and other information between registers and other internal components or units. An external bus is a bus outside of the processor (but inside the computer), moving data, addresses, and other information between major components (including cards) inside the computer. Some common kinds of buses are the system bus, a data bus, an address bus, a cache bus, a memory bus, and an I/O bus.
For more information, see buses.
main storage
Main storage is also called memory or internal memory (to distinguish from external memory, such as hard drives).
RAM is Random Access Memory, and is the basic kind of internal memory. RAM is called “random access” because the processor or computer can access any location in memory (as contrasted with sequential access devices, which must be accessed in order). RAM has been made from reed relays, transistors, integrated circuits, magnetic core, or anything that can hold and store binary values (one/zero, plus/minus, open/close, positive/negative, high/low, etc.). Most modern RAM is made from integrated circuits. At one time the most common kind of memory in mainframes was magnetic core, so many older programmers will refer to main memory as core memory even when the RAM is made from more modern technology. Static RAM is called static because it will continue to hold and store information even when power is removed. Magnetic core and reed relays are examples of static memory. Dynamic RAM is called dynamic because it loses all data when power is removed. Transistors and integrated circuits are examples of dynamic memory. It is possible to have battery back up for devices that are normally dynamic to turn them into static memory.
ROM is Read Only Memory (it is also random access, but only for reads). ROM is typically used to store thigns that will never change for the life of the computer, such as low level portions of an operating system. Some processors (or variations within processor families) might have RAM and/or ROM built into the same chip as the processor (normally used for processors used in standalone devices, such as arcade video games, ATMs, microwave ovens, car ignition systems, etc.). EPROM is Erasable Programmable Read Only Memory, a special kind of ROM that can be erased and reprogrammed with specialized equipment (but not by the processor it is connected to). EPROMs allow makers of industrial devices (and other similar equipment) to have the benefits of ROM, yet also allow for updating or upgrading the software without having to buy new ROM and throw out the old (the EPROMs are collected, erased and rewritten centrally, then placed back into the machines).
Registers and flags are a special kind of memory that exists inside a processor. Typically a processor will have several internal registers that are much faster than main memory. These registers usually have specialized capabilities for arithmetic, logic, and other operations. Registers are usually fairly small (8, 16, 32, or 64 bits for integer data, address, and control registers; 32, 64, 96, or 128 bits for floating point registers). Some processors separate integer data and address registers, while other processors have general purpose registers that can be used for both data and address purposes. A processor will typically have one to 32 data or general purpose registers (processors with separate data and address registers typically split the register set in half). Many processors have special floating point registers (and some processors have general purpose registers that can be used for either integer or floating point arithmetic). Flags are single bit memory used for testing, comparison, and conditional operations (especially conditional branching). For a much more advanced look at registers, see registers.
For more information on memory, see memory
external storage
External storage (also called auxillary storage) is any storage other than main memory. In modern times this is mostly hard drives and removeable media (such as floppy disks, Zip disks, optical media, etc.). With the advent of USB and FireWire hard drives, the line between permanent hard drives and removeable media is blurred. Other kinds of external storage include tape drives, drum drives, paper tape, and punched cards. Random access or indexed access devices (such as hard drives, removeable media, and drum drives) provide an extension of memory (although usually accessed through logical file systems). Sequential access devices (such as tape drives, paper tape punch/readers, or dumb terminals) provide for off-line storage of large amounts of information (or back ups of data) and are often called I/O devices (for input/output).
input/output overview
Most external devices are capable of both input and output (I/O). Some devices are inherently input-only (also called read-only) or inherently output-only (also called write-only). Regardless of whether a device is I/O, read-only, or write-only, external devices can be classified as block or character devices.
A character device is one that inputs or outputs data in a stream of characters, bytes, or bits. Character devices can further be classified as serial or parallel. Examples of character devices include printers, keyboards, and mice.
A serial device streams data as a series of bits, moving data one bit at a time. Examples of serial devices include printers and MODEMs.
A parallel device streams data in a small group of bits simultaneously. Usually the group is a single eight-bit byte (or possibly seven or nine bits, with the possibility of various control or parity bits included in the data stream). Each group usually corresponds to a single character of data. Rarely there will be a larger group of bits (word, longword, doubleword, etc.). The most common parallel device is a printer (although most modern printers have both a serial and a parallel connection, allowing greater connection flexibility).
A block device moves large blocks of data at once. This may be physically implemented as a serial or parallel stream of data, but the entire block gets transferred as single packet of data. Most block devices are random access (that is, information can be read or written from blocks anywhere on the device). Examples of random access block devices include hard disks, floppy disks, and drum drives. Examples of sequential access block devcies include magnetic tape drives and high speed paper tape readers.
input
Input devices are devices that bring information into a computer.
Pure input devices include such things as punched card readers, paper tape readers, keyboards, mice, drawing tablets, touchpads, trackballs, and game controllers.
Devices that have an input component include magnetic tape drives, touchscreens, and dumb terminals.
output
Output devices are devices that bring information out of a computer.
Pure output devices include such things as card punches, paper tape punches, LED displays (for light emitting diodes), monitors, printers, and pen plotters.
Devices that have an output component include magnetic tape drives, combination paper tape reader/punches, teletypes, and dumb terminals.
more details
For a more detailed of the basic parts of a computer, see the following sections:
* processors
o CISC
o RISC
o DSP
o Hybrid
* buses
o kinds of buses
o bus standards
* memory
o memory hardware issues
+ main storage
+ external storage
o basic memory software approaches
+ static and dynamic approaches
+ absolute addressing
+ overlay
+ relocatable software
+ demand paging and swapping
+ program counter relative
+ base pointers
+ indirection, pointers, and handles
+ stack frames
+ virtual memory
o OS memory services
o memory maps
o low memory
For a more detailed examination of how processors work, see assembly language (huge web page) or subsections below:
* intro to assembly language
* data representation and number systems
* registers
* addressing modes
* executable instructions (huge web page, subdivided below)
* data and address movement
* integer arithmetic
* floating arithmetic
* binary coded decimal
* advanced math
* data conversion
* logical operations
* shift and rotate
* bit and bit field manipulation
* character and string
* table operations
* high level language support
* program control and condition codes
* input/output
* system control
* coprocessor and multiprocessor
* trap generating
further reading: books:
If you want your book reviewed, please send a copy to: Milo, POB 1361, Tustin, CA 92781, USA.
Price listings are for courtesy purposes only and may be changed by the referenced businesses at any time without notice.
further reading: books: general
Structured Computer Organization, 4th edition; by Andrew S. Tanenbaum; Prentice Hall; October 1998; ISBN 0130959901; Paperback; 669 pages; $95.00; used by CS 308-273A (Principles of Assembly Languages) at McGill University School of Computer Science
Computers: An Introduction to Hardware and Software Design; by Larry L. Wear, James R. Pinkert (Contributor), William G. Lane (Contributor); McGraw-Hill Higher Education; February 1991; ISBN 0070686742; Hardcover; 544 pages; $98.60; used by CS 308-273A (Principles of Assembly Languages) at McGill University School of Computer Science
In Association with Amazon.com
If you want your book reviewed, please send a copy to: Milo, POB 1361, Tustin, CA 92781, USA.
OSdata.com is used in more than 300 colleges and universities around the world
Read details here.
Some or all of the material on this web page appears in the
free downloadable college text book on computer programming.
A web site on dozens of operating systems simply can’t be maintained by one person. This is a cooperative effort. If you spot an error in fact, grammar, syntax, or spelling, or a broken link, or have additional information, commentary, or constructive criticism, please e-mail Milo. If you have any extra copies of docs, manuals, or other materials that can assist in accuracy and completeness, please send them to Milo, PO Box 1361, Tustin, CA, USA, 92781.
Click here for our privacy policy.
previous page next page
previous page next page
home page
one level up
Hardware Level of Operating System
peer level
* processors
* processes or jobs
* buses
* memory
* memory maps
* low memory
* character codes
A computer is a programmable machine (or more precisely, a programmable sequential state machine). There are two basic kinds of computers: analog and digital.
Analog computers are analog devices. That is, they have continuous states rather than discrete numbered states. An analog computer can represent fractional or irrational values exactly, with no round-off. Analog computers are almost never used outside of experimental settings.
A digital computer is a programmable clocked sequential state machine. A digital computer uses discrete states. A binary digital computer uses two discrete states, such as positive/negative, high/low, on/off, used to represent the binary digits zero and one.
The French word ordinateur, meaning that which puts things in order, is a good description of the most common functionality of computers.
OSdata.com is used in more than 300 colleges and universities around the world
Find out how to get similar high web traffic and search engine placement.
what are computers used for?
Computers are used for a wide variety of purposes.
Data processing is commercial and financial work. This includes such things as billing, shipping and receiving, inventory control, and similar business related functions, as well as the “electronic office”.
Scientific processing is using a computer to support science. This can be as simple as gathering and analyzing raw data and as complex as modelling natural phenomenon (weather and climate models, thermodynamics, nuclear engineering, etc.).
Multimedia includes content creation (composing music, performing music, recording music, editing film and video, special effects, animation, illustration, laying out print materials, etc.) and multimedia playback (games, DVDs, instructional materials, etc.).
parts of a computer
The classic crude oversimplication of a computer is that it contains three elements: processor unit, memory, and I/O (input/output). The borders between those three terms are highly ambigious, non-contiguous, and erratically shifting.
hardware subsystems of a computer
A slightly less crude oversimplification divides a computer into five elements: arithmetic and logic subsystem, control subsystem, main storage, input subsystem, and output subsystem.
* processor
* arithmetic and logic
* control
* main storage
* external storage
* input/output overview
* input
* output
processor
The processor is the part of the computer that actually does the computations. This is sometimes called an MPU (for main processor unit) or CPU (for central processing unit or central processor unit).
A processor typically contains an arithmetic/logic unit (ALU), control unit (including processor flags, flag register, or status register), internal buses, and sometimes special function units (the most common special function unit being a floating point unit for floating point arithmetic).
Some computers have more than one processor. This is called multi-processing.
The major kinds of digital processors are: CISC, RISC, DSP, and hybrid.
CISC stands for Complex Instruction Set Computer. Mainframe computers and minicomputers were CISC processors, with manufacturers competing to offer the most useful instruction sets. Many of the first two generations of microprocessors were also CISC.
RISC stands for Reduced Instruction Set Computer. RISC came about as a result of academic research that showed that a small well designed instruction set running compiled programs at high speed could perform more computing work than a CISC running the same programs (although very expensive hand optimized assembly language favored CISC).
DSP stands for Digital Signal Processing. DSP is used primarily in dedicated devices, such as MODEMs, digital cameras, graphics cards, and other specialty devices.
Hybrid processors combine elements of two or three of the major classes of processors.
For more detailed information on these classes of processors, see processors.
arithmetic and logic
An arithmetic/logic unit (ALU) performs integer arithmetic and logic operations. It also performs shift and rotate operations and other specialized operations. Usually floating point arithmetic is performed by a dedicated floating point unit (FPU), which may be implemented as a co-processor.
An arithmetic/logic unit (ALU) performs integer arithmetic and logic operations. It also performs shift and rotate operations and other specialized operations. Usually floating point arithmetic is performed by a dedicated floating point unit (FPU), which may be implemented as a co-processor.
control
Control units are in charge of the computer. Control units fetch and decode machine instructions. Control units may also control some external devices.
A bus is a set (group) of parallel lines that information (data, addresses, instructions, and other information) travels on inside a computer. Information travels on buses as a series of electrical pulses, each pulse representing a one bit or a zero bit (there are trinary, or three-state, buses, but they are rare). An internal bus is a bus inside the processor, moving data, addresses, instructions, and other information between registers and other internal components or units. An external bus is a bus outside of the processor (but inside the computer), moving data, addresses, and other information between major components (including cards) inside the computer. Some common kinds of buses are the system bus, a data bus, an address bus, a cache bus, a memory bus, and an I/O bus.
For more information, see buses.
main storage
Main storage is also called memory or internal memory (to distinguish from external memory, such as hard drives).
RAM is Random Access Memory, and is the basic kind of internal memory. RAM is called “random access” because the processor or computer can access any location in memory (as contrasted with sequential access devices, which must be accessed in order). RAM has been made from reed relays, transistors, integrated circuits, magnetic core, or anything that can hold and store binary values (one/zero, plus/minus, open/close, positive/negative, high/low, etc.). Most modern RAM is made from integrated circuits. At one time the most common kind of memory in mainframes was magnetic core, so many older programmers will refer to main memory as core memory even when the RAM is made from more modern technology. Static RAM is called static because it will continue to hold and store information even when power is removed. Magnetic core and reed relays are examples of static memory. Dynamic RAM is called dynamic because it loses all data when power is removed. Transistors and integrated circuits are examples of dynamic memory. It is possible to have battery back up for devices that are normally dynamic to turn them into static memory.
ROM is Read Only Memory (it is also random access, but only for reads). ROM is typically used to store thigns that will never change for the life of the computer, such as low level portions of an operating system. Some processors (or variations within processor families) might have RAM and/or ROM built into the same chip as the processor (normally used for processors used in standalone devices, such as arcade video games, ATMs, microwave ovens, car ignition systems, etc.). EPROM is Erasable Programmable Read Only Memory, a special kind of ROM that can be erased and reprogrammed with specialized equipment (but not by the processor it is connected to). EPROMs allow makers of industrial devices (and other similar equipment) to have the benefits of ROM, yet also allow for updating or upgrading the software without having to buy new ROM and throw out the old (the EPROMs are collected, erased and rewritten centrally, then placed back into the machines).
Registers and flags are a special kind of memory that exists inside a processor. Typically a processor will have several internal registers that are much faster than main memory. These registers usually have specialized capabilities for arithmetic, logic, and other operations. Registers are usually fairly small (8, 16, 32, or 64 bits for integer data, address, and control registers; 32, 64, 96, or 128 bits for floating point registers). Some processors separate integer data and address registers, while other processors have general purpose registers that can be used for both data and address purposes. A processor will typically have one to 32 data or general purpose registers (processors with separate data and address registers typically split the register set in half). Many processors have special floating point registers (and some processors have general purpose registers that can be used for either integer or floating point arithmetic). Flags are single bit memory used for testing, comparison, and conditional operations (especially conditional branching). For a much more advanced look at registers, see registers.
For more information on memory, see memory
external storage
External storage (also called auxillary storage) is any storage other than main memory. In modern times this is mostly hard drives and removeable media (such as floppy disks, Zip disks, optical media, etc.). With the advent of USB and FireWire hard drives, the line between permanent hard drives and removeable media is blurred. Other kinds of external storage include tape drives, drum drives, paper tape, and punched cards. Random access or indexed access devices (such as hard drives, removeable media, and drum drives) provide an extension of memory (although usually accessed through logical file systems). Sequential access devices (such as tape drives, paper tape punch/readers, or dumb terminals) provide for off-line storage of large amounts of information (or back ups of data) and are often called I/O devices (for input/output).
input/output overview
Most external devices are capable of both input and output (I/O). Some devices are inherently input-only (also called read-only) or inherently output-only (also called write-only). Regardless of whether a device is I/O, read-only, or write-only, external devices can be classified as block or character devices.
A character device is one that inputs or outputs data in a stream of characters, bytes, or bits. Character devices can further be classified as serial or parallel. Examples of character devices include printers, keyboards, and mice.
A serial device streams data as a series of bits, moving data one bit at a time. Examples of serial devices include printers and MODEMs.
A parallel device streams data in a small group of bits simultaneously. Usually the group is a single eight-bit byte (or possibly seven or nine bits, with the possibility of various control or parity bits included in the data stream). Each group usually corresponds to a single character of data. Rarely there will be a larger group of bits (word, longword, doubleword, etc.). The most common parallel device is a printer (although most modern printers have both a serial and a parallel connection, allowing greater connection flexibility).
A block device moves large blocks of data at once. This may be physically implemented as a serial or parallel stream of data, but the entire block gets transferred as single packet of data. Most block devices are random access (that is, information can be read or written from blocks anywhere on the device). Examples of random access block devices include hard disks, floppy disks, and drum drives. Examples of sequential access block devcies include magnetic tape drives and high speed paper tape readers.
input
Input devices are devices that bring information into a computer.
Pure input devices include such things as punched card readers, paper tape readers, keyboards, mice, drawing tablets, touchpads, trackballs, and game controllers.
Devices that have an input component include magnetic tape drives, touchscreens, and dumb terminals.
output
Output devices are devices that bring information out of a computer.
Pure output devices include such things as card punches, paper tape punches, LED displays (for light emitting diodes), monitors, printers, and pen plotters.
Devices that have an output component include magnetic tape drives, combination paper tape reader/punches, teletypes, and dumb terminals.
more details
For a more detailed of the basic parts of a computer, see the following sections:
* processors
o CISC
o RISC
o DSP
o Hybrid
* buses
o kinds of buses
o bus standards
* memory
o memory hardware issues
+ main storage
+ external storage
o basic memory software approaches
+ static and dynamic approaches
+ absolute addressing
+ overlay
+ relocatable software
+ demand paging and swapping
+ program counter relative
+ base pointers
+ indirection, pointers, and handles
+ stack frames
+ virtual memory
o OS memory services
o memory maps
o low memory
For a more detailed examination of how processors work, see assembly language (huge web page) or subsections below:
* intro to assembly language
* data representation and number systems
* registers
* addressing modes
* executable instructions (huge web page, subdivided below)
* data and address movement
* integer arithmetic
* floating arithmetic
* binary coded decimal
* advanced math
* data conversion
* logical operations
* shift and rotate
* bit and bit field manipulation
* character and string
* table operations
* high level language support
* program control and condition codes
* input/output
* system control
* coprocessor and multiprocessor
* trap generating
further reading: books:
If you want your book reviewed, please send a copy to: Milo, POB 1361, Tustin, CA 92781, USA.
Price listings are for courtesy purposes only and may be changed by the referenced businesses at any time without notice.
further reading: books: general
Structured Computer Organization, 4th edition; by Andrew S. Tanenbaum; Prentice Hall; October 1998; ISBN 0130959901; Paperback; 669 pages; $95.00; used by CS 308-273A (Principles of Assembly Languages) at McGill University School of Computer Science
Computers: An Introduction to Hardware and Software Design; by Larry L. Wear, James R. Pinkert (Contributor), William G. Lane (Contributor); McGraw-Hill Higher Education; February 1991; ISBN 0070686742; Hardcover; 544 pages; $98.60; used by CS 308-273A (Principles of Assembly Languages) at McGill University School of Computer Science
In Association with Amazon.com
If you want your book reviewed, please send a copy to: Milo, POB 1361, Tustin, CA 92781, USA.
OSdata.com is used in more than 300 colleges and universities around the world
Read details here.
Some or all of the material on this web page appears in the
free downloadable college text book on computer programming.
A web site on dozens of operating systems simply can’t be maintained by one person. This is a cooperative effort. If you spot an error in fact, grammar, syntax, or spelling, or a broken link, or have additional information, commentary, or constructive criticism, please e-mail Milo. If you have any extra copies of docs, manuals, or other materials that can assist in accuracy and completeness, please send them to Milo, PO Box 1361, Tustin, CA, USA, 92781.
Click here for our privacy policy.
previous page next page
previous page next page
home page
one level up
Hardware Level of Operating System
peer level
* processors
* processes or jobs
* buses
* memory
* memory maps
* low memory
* character codes
Computer Intelligence Applications
INTRODUCTION
The word 'robot' evokes many different thoughts and images, perhaps conflicting ones. Some may think of a metal humanoid, others of an industrial arm, and yet more may think, unfortunately, of a lost job. In the field of medical robotics, the word robot is just as fuzzily defined, with many different applications. These range from simplistic laboratory robots, to highly complex surgical robots that can either aid a human surgeon or execute operations by themselves.
The idea of robotics in surgery got its start in the military. The idea was to develop technology where a surgeon could perform an operation from a remote location on an injured soldier in the battlefield. This concept has evolved into robotics to enhance surgical performance. In this instance, a robotic arm called Endowrist performs the procedure with the surgeon guiding the robotic arm from a location in or adjacent to the operating room. The surgeon sits at a station peering at a monitor that shows a magnified view of the surgical field. A computer mimics and enhances his hand movements. The computer in this instance makes the movements more precise by dampening even a tiny tremor in the surgeon's hands, which might increase the difficulty in performing procedures under high power microscopic magnification. Examples of such procedures now being performed that were extremely difficult if not impossible before this technology are fallopian tube repair in women, microsurgery on the fetus, and minimally invasive coronary bypass surgery. The Zeus robot made by Computer Motion and a similar device, the Endowrist made by Intuitive Surgical are now in clinical trials for the above-mentioned procedures. Even with the robot to enhance the surgeon's ability, a great deal of practice is required to master the technique.
The reasons behind the interest in the adoption of medical robots are multitudinous. There is a great analogy to be found with the automation involved in the manufacturing industry. That is not to say that the issues of medical robotics are the same, but that the advantages to be gained are similar. Robots provide industry with something that is, to them, more valuable than even the most dedicated and hard-working employee - namely speed, accuracy, repeatability, reliability, and cost-efficiency. A robotic aid, for example, one that holds a viewing instrument for a surgeon, will not become fatigued, for however long it is used. It will position the instrument accurately with no tremor, and it will be able to perform just as well on the 100th occasion as it did on the first. The use of robotics and computers in minimally invasive spine surgery has resulted in more accurate surgical procedures, shortened operative time and fewer complications. It is expected that Computer Enhanced Image Guidance Systems will improve the precision of these procedures as a result of real time 3-D imaging at the time of the surgery. Diagnostic studies will be digitally transmitted to the operating room and projected to monitors to further aid the surgeon in performing the correct procedure with minimal trauma to the patient
SURGICAL NAVIGATION SYSTEM
A surgical navigation system has been built that is currently used regularly for neurosurgical cases such as tumor resection at Brigham and Women's Hospital. The system consists of a portable cart containing a Sun UltraSPARC workstation and the hardware to drive the laser scanner and Flashpoint tracking system (Image Guided Technologies, Boulder, CO). On top of the cart is mounted an articulated extendible arm to which a bar is attached to house the laser scanner and Flashpoint cameras. The three linear Flashpoint cameras are inside the bar. The laser is attached to one end of the bar, and a video camera to the other. The joint between the arm and scanning bar has three degrees-of-freedom to allow easy placement of the bar in desired configurations
The word 'robot' evokes many different thoughts and images, perhaps conflicting ones. Some may think of a metal humanoid, others of an industrial arm, and yet more may think, unfortunately, of a lost job. In the field of medical robotics, the word robot is just as fuzzily defined, with many different applications. These range from simplistic laboratory robots, to highly complex surgical robots that can either aid a human surgeon or execute operations by themselves.
The idea of robotics in surgery got its start in the military. The idea was to develop technology where a surgeon could perform an operation from a remote location on an injured soldier in the battlefield. This concept has evolved into robotics to enhance surgical performance. In this instance, a robotic arm called Endowrist performs the procedure with the surgeon guiding the robotic arm from a location in or adjacent to the operating room. The surgeon sits at a station peering at a monitor that shows a magnified view of the surgical field. A computer mimics and enhances his hand movements. The computer in this instance makes the movements more precise by dampening even a tiny tremor in the surgeon's hands, which might increase the difficulty in performing procedures under high power microscopic magnification. Examples of such procedures now being performed that were extremely difficult if not impossible before this technology are fallopian tube repair in women, microsurgery on the fetus, and minimally invasive coronary bypass surgery. The Zeus robot made by Computer Motion and a similar device, the Endowrist made by Intuitive Surgical are now in clinical trials for the above-mentioned procedures. Even with the robot to enhance the surgeon's ability, a great deal of practice is required to master the technique.
The reasons behind the interest in the adoption of medical robots are multitudinous. There is a great analogy to be found with the automation involved in the manufacturing industry. That is not to say that the issues of medical robotics are the same, but that the advantages to be gained are similar. Robots provide industry with something that is, to them, more valuable than even the most dedicated and hard-working employee - namely speed, accuracy, repeatability, reliability, and cost-efficiency. A robotic aid, for example, one that holds a viewing instrument for a surgeon, will not become fatigued, for however long it is used. It will position the instrument accurately with no tremor, and it will be able to perform just as well on the 100th occasion as it did on the first. The use of robotics and computers in minimally invasive spine surgery has resulted in more accurate surgical procedures, shortened operative time and fewer complications. It is expected that Computer Enhanced Image Guidance Systems will improve the precision of these procedures as a result of real time 3-D imaging at the time of the surgery. Diagnostic studies will be digitally transmitted to the operating room and projected to monitors to further aid the surgeon in performing the correct procedure with minimal trauma to the patient
SURGICAL NAVIGATION SYSTEM
A surgical navigation system has been built that is currently used regularly for neurosurgical cases such as tumor resection at Brigham and Women's Hospital. The system consists of a portable cart containing a Sun UltraSPARC workstation and the hardware to drive the laser scanner and Flashpoint tracking system (Image Guided Technologies, Boulder, CO). On top of the cart is mounted an articulated extendible arm to which a bar is attached to house the laser scanner and Flashpoint cameras. The three linear Flashpoint cameras are inside the bar. The laser is attached to one end of the bar, and a video camera to the other. The joint between the arm and scanning bar has three degrees-of-freedom to allow easy placement of the bar in desired configurations
Biological Computers
INTRODUCTION
Biological computers have emerged as an interdisciplinary field that draws together molecular biology, chemistry, computer science and mathematics. The highly predictable hybridization chemistry of DNA, the ability to completely control the length and content of oligonucleotides, and the wealth of enzymes available for modification of the DNA, make the use of nucleic acids an attractive candidate for all of these nanoscale applications
A 'DNA computer' has been used for the first time to find the only correct answer from over a million possible solutions to a computational problem. Leonard Adleman of the University of Southern California in the US and colleagues used different strands of DNA to represent the 20 variables in their problem, which could be the most complex task ever solved without a conventional computer. The researchers believe that the complexity of the structure of biological molecules could allow DNA computers to outperform their electronic counterparts in future.
Scientists have previously used DNA computers to crack computational problems with up to nine variables, which involves selecting the correct answer from 512 possible solutions. But now Adleman's team has shown that a similar technique can solve a problem with 20 variables, which has 220 - or 1 048 576 - possible solutions.
Adleman and colleagues chose an 'exponential time' problem, in which each extra variable doubles the amount of computation needed. This is known as an NP-complete problem, and is notoriously difficult to solve for a large number of variables. Other NP-complete problems include the 'travelling salesman' problem - in which a salesman has to find the shortest route between a number of cities - and the calculation of interactions between many atoms or molecules.
Adleman and co-workers expressed their problem as a string of 24 'clauses', each of which specified a certain combination of 'true' and 'false' for three of the 20 variables. The team then assigned two short strands of specially encoded DNA to all 20 variables, representing 'true' and 'false' for each one.
In the experiment, each of the 24 clauses is represented by a gel-filled glass cell. The strands of DNA corresponding to the variables - and their 'true' or 'false' state - in each clause were then placed in the cells.
Each of the possible 1,048,576 solutions were then represented by much longer strands of specially encoded DNA, which Adleman's team added to the first cell. If a long strand had a 'subsequence' that complemented all three short strands, it bound to them. But otherwise it passed through the cell.
To move on to the second clause of the formula, a fresh set of long strands was sent into the second cell, which trapped any long strand with a 'subsequence' complementary to all three of its short strands. This process was repeated until a complete set of long strands had been added to all 24 cells, corresponding to the 24 clauses. The long strands captured in the cells were collected at the end of the experiment, and these represented the solution to the problem.
THE WORLD'S SMALLEST COMPUTER
The world's smallest computer (around a trillion can fit in a drop of water) might one day go on record again as the tiniest medical kit. Made entirely of biological molecules, this computer was successfully programmed to identify - in a test tube - changes in the balance of molecules in the body that indicate the presence of certain cancers, to diagnose the type of cancer, and to react by producing a drug molecule to fight the cancer cells.
DOCTOR IN A CELL
In previous biological computers produced input, output and "software" are all composed of DNA, the material of genes, while DNA-manipulating enzymes are used as "hardware." The newest version's input apparatus is designed to assess concentrations of specific RNA molecules, which may be overproduced or under produced, depending on the type of cancer. Using pre-programmed medical knowledge, the computer then makes its diagnosis based on the detected RNA levels. In response to a cancer diagnosis, the output unit of the computer can initiate the controlled release of a single-stranded DNA molecule that is known to interfere with the cancer cell's activities, causing it to self-destruct.
Biological computers have emerged as an interdisciplinary field that draws together molecular biology, chemistry, computer science and mathematics. The highly predictable hybridization chemistry of DNA, the ability to completely control the length and content of oligonucleotides, and the wealth of enzymes available for modification of the DNA, make the use of nucleic acids an attractive candidate for all of these nanoscale applications
A 'DNA computer' has been used for the first time to find the only correct answer from over a million possible solutions to a computational problem. Leonard Adleman of the University of Southern California in the US and colleagues used different strands of DNA to represent the 20 variables in their problem, which could be the most complex task ever solved without a conventional computer. The researchers believe that the complexity of the structure of biological molecules could allow DNA computers to outperform their electronic counterparts in future.
Scientists have previously used DNA computers to crack computational problems with up to nine variables, which involves selecting the correct answer from 512 possible solutions. But now Adleman's team has shown that a similar technique can solve a problem with 20 variables, which has 220 - or 1 048 576 - possible solutions.
Adleman and colleagues chose an 'exponential time' problem, in which each extra variable doubles the amount of computation needed. This is known as an NP-complete problem, and is notoriously difficult to solve for a large number of variables. Other NP-complete problems include the 'travelling salesman' problem - in which a salesman has to find the shortest route between a number of cities - and the calculation of interactions between many atoms or molecules.
Adleman and co-workers expressed their problem as a string of 24 'clauses', each of which specified a certain combination of 'true' and 'false' for three of the 20 variables. The team then assigned two short strands of specially encoded DNA to all 20 variables, representing 'true' and 'false' for each one.
In the experiment, each of the 24 clauses is represented by a gel-filled glass cell. The strands of DNA corresponding to the variables - and their 'true' or 'false' state - in each clause were then placed in the cells.
Each of the possible 1,048,576 solutions were then represented by much longer strands of specially encoded DNA, which Adleman's team added to the first cell. If a long strand had a 'subsequence' that complemented all three short strands, it bound to them. But otherwise it passed through the cell.
To move on to the second clause of the formula, a fresh set of long strands was sent into the second cell, which trapped any long strand with a 'subsequence' complementary to all three of its short strands. This process was repeated until a complete set of long strands had been added to all 24 cells, corresponding to the 24 clauses. The long strands captured in the cells were collected at the end of the experiment, and these represented the solution to the problem.
THE WORLD'S SMALLEST COMPUTER
The world's smallest computer (around a trillion can fit in a drop of water) might one day go on record again as the tiniest medical kit. Made entirely of biological molecules, this computer was successfully programmed to identify - in a test tube - changes in the balance of molecules in the body that indicate the presence of certain cancers, to diagnose the type of cancer, and to react by producing a drug molecule to fight the cancer cells.
DOCTOR IN A CELL
In previous biological computers produced input, output and "software" are all composed of DNA, the material of genes, while DNA-manipulating enzymes are used as "hardware." The newest version's input apparatus is designed to assess concentrations of specific RNA molecules, which may be overproduced or under produced, depending on the type of cancer. Using pre-programmed medical knowledge, the computer then makes its diagnosis based on the detected RNA levels. In response to a cancer diagnosis, the output unit of the computer can initiate the controlled release of a single-stranded DNA molecule that is known to interfere with the cancer cell's activities, causing it to self-destruct.
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