A general-purpose machine that processes data according to a set of instructions that are stored internally either temporarily or permanently. The computer and all equipment attached to it are called hardware. The instructions that tell it what to do are called "software." A set of instructions that perform a particular task is called a "program" or "software program."
What a Computer Does
The instructions in the program direct the computer to input, process and output as follows:
Input/Output
The computer can selectively retrieve data into its main memory (RAM) from any peripheral device (terminal, disk, tape, etc.) connected to it. After processing the data internally, the computer can send a copy of the results from its memory out to any peripheral device. The more memory it has, the more programs and data it can work with at the same time.
Storage
By outputting data onto a magnetic disk or tape, the computer is able to store data permanently and retrieve it when required. A system's size is based on how much disk storage it has. The more disk, the more data are immediately available.
Processing (The 3 C's)
The computer performs all processing by "calculating," "comparing" and "copying" the data stored in its memory (RAM).
Calculate
The computer can perform any mathematical operation on data by adding, subtracting, multiplying and dividing one set with another.
Compare
The computer can analyze and evaluate data by matching it with sets of known data that are included in the program or called in from storage.
Copy
The computer can move data around to create any kind of report or listing in any order.
Calculate, Compare and Copy
By calculating, comparing and copying, the computer accomplishes all forms of data processing. For example, records are sorted into a new order by comparing two records at a time and copying the record with the lower value in front of the one with the higher value.
The computer finds one customer out of thousands by comparing the requested account number to each record in the file. The query statement: SUM SALARY FOR TITLE = "NURSE" causes the computer to compare the title field in each record for NURSE and then add (calculate) the salary field for each match.
In word processing, inserting and deleting text is accomplished by copying characters from one place to another.
Remember The 3 C's
If you wonder whether the computer can solve a problem, identify your data on paper. If it can be calculated, compared and copied on paper, it can be processed in the computer.
The 3 C's - Finding Things
This example counts all California records in the database by comparing each record with "CA." Every record in the database is read into memory. The memory locations that state is written into are compared with the letters "CA" in the program. If they are equal, a "1" is added to the California counter. The second record is written into the same memory bytes as the first record, and the field is compared again. This process is performed until the last record has been examined.
The 3 C's - Displaying and Printing
Data are stored as contiguous fields in the database with no blanks in between. The data are displayed and printed the way we like to see it by writing the data into memory and copying the characters into the desired order. The date in this example is printed through a "picture," which is a set of characters that acts as a filter. Each character in the date is compared to a corresponding character in the picture, and the one copied as output is determined by the rules. Pictures can be implemented in software or in hardware.
The 3 C's - Sorting
Sorting, or resequencing, data is accomplished by comparing each item of data with the others and copying it into the appropriate order. Of course, there is a ton of calculating going on to keep track of what is being compared. Years ago, when databases were stored on tape, the speed of a vendor's sort program was a powerful marketing feature. All transactions had to be sorted into account number sequence in order to be processed. In today's online systems, data are often indexed. Instead of sorting the actual data records themselves, the much smaller indexes are sorted.
The 3 C's - Editing
The magic of word processing is nothing more than copying text. In this example, in order for the "O" to be inserted into the word, the remaining characters are copied one memory location (byte) to the right to make room for it. Deleting is copying in reverse. As in all data processing, there is a whole lot of calculating and comparing going on to keep track of where the text is stored in memory.
The Stored Program Concept
The computer's ability to call in instructions and follow them is known as the "stored program concept." Instructions are copied into memory from a disk, tape or other source before any data can be processed. The computer is directed to start with the first instruction in the program. It copies the instruction from memory into its control unit circuit and matches it against its built-in set of instructions. If the instruction is valid, the processor carries it out. If not, the computer comes to an abnormal end (see crash).
The computer executes instructions sequentially until it finds a GOTO instruction that tells it to go to a different place in the program. It can execute billions of instructions per second, using the same program logic on each new set of data brought in.
Operations Overlap
Input/output and processing are made to overlap. While one program is waiting for input from one user, the operating system (master control program) directs the computer to process data in another program. Large computers allow many input/output operations to occur simultaneously with processing.
It can take hundreds of thousands of discrete machine steps to perform very routine tasks. Your computer could easily execute several million instructions to put a requested record on screen for you.
Computer Generations
First-generation computers, starting with the UNIVAC I in 1951, used vacuum tubes, and their memories were made of thin tubes of liquid mercury and magnetic drums.
Second-generation systems in the late 1950s replaced tubes with transistors and used magnetic cores for memories (IBM 1401, Honeywell 800). Size was reduced and reliability was significantly improved.
Third-generation computers, beginning in the mid-1960s, used the first integrated circuits (IBM 360, CDC 6400) and the first operating systems and DBMSs. Online systems were widely developed, although most processing was still batch oriented using punch cards and magnetic tapes.
Starting in the mid-1970s, the fourth generation brought us computers made entirely of chips. It spawned the microprocessor and personal computer. It introduced distributed processing and office automation. Query languages, report writers and spreadsheets put large numbers of people in touch with the computer for the first time. Even with the hundreds of millions of people using computers every day, we are still in the fourth generation. Some skill is still required to use the computer even if only to surf the Web and send e-mail.
The fifth generation implies faster hardware and more sophisticated software that uses artificial intelligence (AI) routinely. Natural language recognition is a major component of the fifth generation. When you can have a reasonably intelligent conversation with the average computer, you will be in the fifth generation, perhaps in the 2015-2020 time frame.
The Beginning of Commercial Computing
In the early 1950s, the UNIVAC I ushered in the computer age. This picture was taken in Frankfurt, Germany in 1956 and shows the console on the right, a little more than half the CPU on the left and the tape drives in the background.
The Installation
This picture, taken in 1956, shows half the CPU of the UNIVAC I. Imagine yourself watching this awesome sight and someone says to you, "in 20 years, everything you see being wheeled up the ramp will fit on the tip of your finger." Would you have believed it?
Types of Computers
Computers can be as small as a chip or as large as a truck. The difference is in the amount of work they do within the same time frame. Its power is based on many factors, including word size and the speed of its CPU, memory and peripherals. Following is a "rough" guide to system cost.
What a Computer Does
The instructions in the program direct the computer to input, process and output as follows:
Input/Output
The computer can selectively retrieve data into its main memory (RAM) from any peripheral device (terminal, disk, tape, etc.) connected to it. After processing the data internally, the computer can send a copy of the results from its memory out to any peripheral device. The more memory it has, the more programs and data it can work with at the same time.
Storage
By outputting data onto a magnetic disk or tape, the computer is able to store data permanently and retrieve it when required. A system's size is based on how much disk storage it has. The more disk, the more data are immediately available.
Processing (The 3 C's)
The computer performs all processing by "calculating," "comparing" and "copying" the data stored in its memory (RAM).
Calculate
The computer can perform any mathematical operation on data by adding, subtracting, multiplying and dividing one set with another.
Compare
The computer can analyze and evaluate data by matching it with sets of known data that are included in the program or called in from storage.
Copy
The computer can move data around to create any kind of report or listing in any order.
Calculate, Compare and Copy
By calculating, comparing and copying, the computer accomplishes all forms of data processing. For example, records are sorted into a new order by comparing two records at a time and copying the record with the lower value in front of the one with the higher value.
The computer finds one customer out of thousands by comparing the requested account number to each record in the file. The query statement: SUM SALARY FOR TITLE = "NURSE" causes the computer to compare the title field in each record for NURSE and then add (calculate) the salary field for each match.
In word processing, inserting and deleting text is accomplished by copying characters from one place to another.
Remember The 3 C's
If you wonder whether the computer can solve a problem, identify your data on paper. If it can be calculated, compared and copied on paper, it can be processed in the computer.
The 3 C's - Finding Things
This example counts all California records in the database by comparing each record with "CA." Every record in the database is read into memory. The memory locations that state is written into are compared with the letters "CA" in the program. If they are equal, a "1" is added to the California counter. The second record is written into the same memory bytes as the first record, and the field is compared again. This process is performed until the last record has been examined.
The 3 C's - Displaying and Printing
Data are stored as contiguous fields in the database with no blanks in between. The data are displayed and printed the way we like to see it by writing the data into memory and copying the characters into the desired order. The date in this example is printed through a "picture," which is a set of characters that acts as a filter. Each character in the date is compared to a corresponding character in the picture, and the one copied as output is determined by the rules. Pictures can be implemented in software or in hardware.
The 3 C's - Sorting
Sorting, or resequencing, data is accomplished by comparing each item of data with the others and copying it into the appropriate order. Of course, there is a ton of calculating going on to keep track of what is being compared. Years ago, when databases were stored on tape, the speed of a vendor's sort program was a powerful marketing feature. All transactions had to be sorted into account number sequence in order to be processed. In today's online systems, data are often indexed. Instead of sorting the actual data records themselves, the much smaller indexes are sorted.
The 3 C's - Editing
The magic of word processing is nothing more than copying text. In this example, in order for the "O" to be inserted into the word, the remaining characters are copied one memory location (byte) to the right to make room for it. Deleting is copying in reverse. As in all data processing, there is a whole lot of calculating and comparing going on to keep track of where the text is stored in memory.
The Stored Program Concept
The computer's ability to call in instructions and follow them is known as the "stored program concept." Instructions are copied into memory from a disk, tape or other source before any data can be processed. The computer is directed to start with the first instruction in the program. It copies the instruction from memory into its control unit circuit and matches it against its built-in set of instructions. If the instruction is valid, the processor carries it out. If not, the computer comes to an abnormal end (see crash).
The computer executes instructions sequentially until it finds a GOTO instruction that tells it to go to a different place in the program. It can execute billions of instructions per second, using the same program logic on each new set of data brought in.
Operations Overlap
Input/output and processing are made to overlap. While one program is waiting for input from one user, the operating system (master control program) directs the computer to process data in another program. Large computers allow many input/output operations to occur simultaneously with processing.
It can take hundreds of thousands of discrete machine steps to perform very routine tasks. Your computer could easily execute several million instructions to put a requested record on screen for you.
Computer Generations
First-generation computers, starting with the UNIVAC I in 1951, used vacuum tubes, and their memories were made of thin tubes of liquid mercury and magnetic drums.
Second-generation systems in the late 1950s replaced tubes with transistors and used magnetic cores for memories (IBM 1401, Honeywell 800). Size was reduced and reliability was significantly improved.
Third-generation computers, beginning in the mid-1960s, used the first integrated circuits (IBM 360, CDC 6400) and the first operating systems and DBMSs. Online systems were widely developed, although most processing was still batch oriented using punch cards and magnetic tapes.
Starting in the mid-1970s, the fourth generation brought us computers made entirely of chips. It spawned the microprocessor and personal computer. It introduced distributed processing and office automation. Query languages, report writers and spreadsheets put large numbers of people in touch with the computer for the first time. Even with the hundreds of millions of people using computers every day, we are still in the fourth generation. Some skill is still required to use the computer even if only to surf the Web and send e-mail.
The fifth generation implies faster hardware and more sophisticated software that uses artificial intelligence (AI) routinely. Natural language recognition is a major component of the fifth generation. When you can have a reasonably intelligent conversation with the average computer, you will be in the fifth generation, perhaps in the 2015-2020 time frame.
The Beginning of Commercial Computing
In the early 1950s, the UNIVAC I ushered in the computer age. This picture was taken in Frankfurt, Germany in 1956 and shows the console on the right, a little more than half the CPU on the left and the tape drives in the background.
The Installation
This picture, taken in 1956, shows half the CPU of the UNIVAC I. Imagine yourself watching this awesome sight and someone says to you, "in 20 years, everything you see being wheeled up the ramp will fit on the tip of your finger." Would you have believed it?
Types of Computers
Computers can be as small as a chip or as large as a truck. The difference is in the amount of work they do within the same time frame. Its power is based on many factors, including word size and the speed of its CPU, memory and peripherals. Following is a "rough" guide to system cost.
Type of Approximate Cost Computer In 2006 US $ Chips Microcontroller (MCU) (4, 8, 32, 16-bit) $1 - $150 Microprocessor chip (4, 8, 16, 32, 64-bit) $5 - $1K Client Systems Desktop/laptop client (32, 64-bit) $400 - $6K Workstation (32, 64-bit) $5K - $25K Server Systems Low end server (32, 64-bit) $2K - 5K Midrange server (32, 64-bit) $15K - 250K High-end server/mainframe (32, 64-bit) $500K - $3M Supercomputer (64-bit) $1M - $5M K = thousand $ M = million $
 | Reproduced with permission from Computer Desktop Encyclopedia. Copyright (c) 1981-2008 The Computer Language Company Inc. All rights reserved. |
Additional Resources
- Student Technology Day: Steve Ballmer Q&A
- There was quite a lot to transcribe out, and many questions asked. Some questions put to Steve Ballmer, CEO of Microsoft, include: Will we always need programmers? What's Microsoft's input in Facebook and social networking? Does Microsoft have any changes in mind for their...
- Blog posts 2008-10-06
- Test drive: First checkpoint-friendly computer bag
- Back in August TSA issued new guidelines for travelers with notebook computers that would, for the first time, allow passengers to keep them in their bags while passing through the x-ray scanner. The TSA implemented its checkpoint-friendly bag policy on 16 August 2008 and to qualify as...
- Blog posts 2008-10-06
- Welcome to the Data Cloud ?
- ‘The Cloud' is increasingly prevalent in tech conversation these days. Stalwarts of the space such as Amazon and Salesforce go from strength to strength, whilst titans of an earlier model such as Larry Ellison and even Steve Ballmer now seek to appropriate the meme. New blogs like CloudAve play a...
- Blog posts 2008-10-06
- Two Europeans indicted for US cyberattacks
- The indictments are part of the FBI's Operation Cyberslam, said to be the US's first successful investigation into a large-scale, commercially motivated denial-of-service attack Two Europeans, one of whom is English, have been indicted by a US federal grand jury in connection with a 2003 distributed denial-of-service attack that...
- News items 2008-10-06
- The top five reasons why Windows Vista failed
- On Friday, Microsoft gave computer makers a six-month extension for offering Windows XP on newly-shipped PCs. While this doesn't impact enterprise IT -- because volume licensing agreements will allow IT to keep installing Windows XP for many years to come -- the move is another symbolic nail in Vista's coffin....
- Blog posts 2008-10-06
- The cloud finally comes to education
- Cloud computing is one of those great buzzwords in IT that, so far, has meant very little to the average Ed Tech customer. We all have a pretty good idea what it means: lots of computers somewhere (we don't actually care where) doing lots of processing to deliver services...
- Blog posts 2008-10-06
- Why bother with desktop virtualization?
- The proponents of making proper use of desktop virtualization technology including access virtualization, application virtualization and VDI the combination of access virtualization and processing virtualization do their best to make it sound like the best things since pockets. Aren't today's laptops, desktops and handheld devices good enough to get the...
- Blog posts 2008-10-06
- Techies choose Obama - by a landslide
- If techies could choose the next President, Obama would win in a landslide. Checking donors from 10 large tech companies, including Apple, Dell, Google and Microsoft, over 90% of the donations support the senator from Illinois. Why does high-tech love Obama? First the numbers The...
- Blog posts 2008-10-05
- Hands-on review of the Logitech Squeezebox Boom
- After seeing my mildly skeptical post about the release of its Squeezebox Boom Internet radio device, Logitech offered to send me a sample unit to review, promising me I'd be pleasantly surprised with the audio output from the compact unit. I've been testing it out over the last few weeks,...
- Blog posts 2008-10-04
- The quad-core laptops are here . . . sort of
- Back in August Dell, HP and Lenovo all announced mobile workstations that offer Intel's first quad-core chip for laptops. Those systems are now available for order and reviews of at least one model--the Lenovo ThinkPad W700--are giving a glimpse of the performance you can expect from these 17-inch powerhouses. ...
- Blog posts 2008-10-03
- Well, I do actually worry (about mobile viruses)
- Well, I do actually worry about mobile virusesIt's all economics...Most crackers hackers gone bad are doing this for monetary gain so like most people want to put the minimal amount effort to get the maximum gain. Mobile devices are such a nice diverse group of devices that crackers haven't found...
- Discussion threads 2008-10-03
- My growing hatred for calculators
- My growing hatred for calculatorsNokids need to think mathematically when doing math and programmatically when programming and literarily when reading literature, etc.Spreadsheeting for math? Joy. We all get to castrate mathematical symbology in order to shoehorn it into a spreadsheet cell t=sqrt(a^3)Wonderful.I guess when the only thing you know is...
- Discussion threads 2008-10-03
- Mac ready the enterprise?
- Mac ready the enterprise?My work MacBook Pro just experienced this very problem...My work MacBook Pro just experienced this very problem. When I'm at home I connect it to my external 22" CRT, keyboard, mouse, etc. It stays there until I get back to work where I use it...
- Discussion threads 2008-10-03
- Mimicking electric eel cells to produce energy
- A team of U.S. engineers has found that it's possible to build artificial cells replicating the electrical behavior of electric eel cells. In fact, these artificial cells deliver better performance than the real ones, called electrocytes, which can generate electric potentials of up to 600 volts. The researchers have developed...
- Blog posts 2008-10-03
- Our second Linux laptop has a real keyboard
- Our second Linux laptop has a real keyboardXandros lite is OK ...For the average user the Xandros Lite OS is fine, but it does have some shortcomings:1) Asus for some reason has a ram limit compiled into the kernel of 1GB. The machine has a max limit of 2GB, but...
- Discussion threads 2008-10-03
- Mac ready for the enterprise?
- Larry Dignan makes a spirited argument as to why Apple should be working much harder on getting Mac kit into the enterprise. I know it's a Friday afternoon for me and we've already had one false alarm earlier today that got everyone a-Twitter. Only the other day I managed to...
- Blog posts 2008-10-03
- Slimming down the bloated iTunes 8 installer
- Slimming down the bloated iTunes 8 installerPerformance?Let alone the installer size, does anyone else out there have kind of mediocre performance with iTunes in Windows Vista? I've had a number of times where it just seems to come up black, or respond slowly, or syncing just slows my PC to...
- Discussion threads 2008-10-03
- Microsoft launches software for cheap Portuguese laptop
- Microsoft launches software for cheap Portuguese laptopMicrosoft launches software for cheap Portuguese laptopThis is a great plan brought to you by Microsoft. This laptop will run the Microsoft Windows XP operating system allowing these school children to be compatible with the rest of the world. They can share...
- Discussion threads 2008-10-03
- Put your PC on an energy diet!
- Put your PC on an energy diet!The wonders of USB and Firewire...Almost all of my new "toys" are either USB or Firewire; I don't know how much power these things draw when they're not in active use, but the really infrequently used ones can at least be hot-plugged on demand.But...
- Discussion threads 2008-10-03
- Microsoft launches software for cheap Portuguese laptop
- Microsoft launched on Friday a software package for a Portuguese ultra-cheap laptop for school children that the government hopes will boost the country's technological edge in education. LISBON--Microsoft launched on Friday a software package for a Portuguese ultra-cheap laptop for school children that the government hopes will boost the...
- News items 2008-10-03
Neighboring Terms
Premier Vendor Content Whitepapers, webcasts & resources from our Power Center Sponsors
- Marc Canter: The master of multimedia speaks
-
In this Super Techies interview, larger-than-life techie Marc Canter talks with ZDNet's Editor in Chief Dan Farber about his career as a multimedia pioneer.
- Watch the video >>
- Access the latest Intel and industry best practices
-
Designed specifically to address the concerns of senior IT managers at organizations with more than 100 employees, the Intel Premier IT Professional Program provides best practices via local and e-Seminars and a members-only Web site.
- View the Intel Premier IT Professional web-site tour >>
