Part A: Computers
Foundations of computing
Key takeaways
- Data is unprocessed facts; it becomes information once it is arranged, summarised or interpreted for a specific reader.
- A bit is a single 0 or 1 and a byte is eight bits; storage climbs in steps of 1,024, from bytes to KB, MB and GB.
- A computer system needs five elements working together: hardware, software, data, procedures and people. Take any one away and the rest cannot produce output.
- Hardware is what can be touched, software is the programs, procedures and data that instruct it, and a program is one set of instructions for one specific job.
- Computers fall into five generations, from vacuum tubes to artificial intelligence, and are classified by size, by type (analog, digital, hybrid) and by purpose (general or special).
A CAMS technician's day-to-day work, whether posting a receipt into an accounting package or filing a returns schedule, runs through a computer, so this opening chapter fixes the working vocabulary everything else in the paper leans on:
- The building blocks a machine actually manipulates.
- The difference between a computer and the wider activity of computing.
- The five elements a working system needs together.
- The broad families of machine the syllabus expects you to be able to name and place.
Key terms
Computer
A computer is an electronic device that accepts data as input, processes it under a set of stored instructions, and produces information as output, while storing data and instructions for later use. Its defining traits are speed, accuracy when correctly instructed, storage capacity, diligence, working tirelessly through repetitive tasks without loss of concentration, and versatility, the same machine can run a payroll, mark an exam or edit a photograph depending only on the program loaded.
Computing
Computing is the broader activity of using and developing computer technology, hardware and software, to process data, solve problems and manage information. A computer is a physical device; computing is the discipline around it, designing algorithms, writing programs, managing networks and analysing data are all computing, whether or not a single machine is in view at the time.
Computer system
None of hardware, software or data does anything useful on its own; a computer system is what results once five parts are brought together and working as one, and taking any single one away leaves the rest unable to produce output.
- Hardware: the physical machine itself
- Software: the instructions telling that machine what to do
- Data: what actually gets fed in and worked on
- Procedures: the agreed rules and steps for running the system correctly and consistently
- People: whoever is operating it, from the clerk keying in a day's receipts to the administrator maintaining the server
Hardware
Hardware is the physical, tangible part of a computer system, everything that can be touched: the case, the motherboard, the processor, the keyboard, the monitor and every other physical component. Hardware on its own cannot do anything useful; it needs software to instruct it, covered in full in the chapter on software.
Software
Where hardware is what can be touched, software is what cannot: the programs, the procedures around them, and the data they work with, all of it existing only on a storage medium until it is loaded and run. It is software, not the hardware itself, that turns a general-purpose machine into whatever specific tool a person actually needs at that moment.
Program
A single program is one narrow set of instructions for one specific job, sorting a customer list into alphabetical order, say, or totalling a column of figures. What gets called 'a piece of software' is usually many such programs bundled together with the data and documentation that support them, a word processor being a familiar example of that bundling.
Information and communication technology
Information Communication Technology (ICT) combines computing technology, hardware and software for processing data, with telecommunications technology, equipment and networks for transmitting it, covering everything used to create, store, process, transmit, retrieve and exchange information electronically, from a single desktop computer to the global internet.
Computer generations
History divides computers into five generations, one for every step-change in the underlying technology that built them.
| Generation | Core technology | Approximate period | Notable feature |
|---|---|---|---|
| First | Vacuum tubes | 1940s to mid-1950s | Huge, generated enormous heat, and used machine language directly; example: ENIAC. |
| Second | Transistors | Mid-1950s to mid-1960s | Smaller, faster and more reliable than vacuum tubes, and programmed in early high-level languages such as COBOL and FORTRAN. |
| Third | Integrated circuits (ICs) | Mid-1960s to mid-1970s | Many transistors etched onto a single chip, giving a further jump in speed and reliability and the first use of operating systems. |
| Fourth | Microprocessors (VLSI) | Mid-1970s to late 2000s | An entire processor on one chip, making the personal computer possible; most desktops and laptops in use today are fourth-generation machines. |
| Fifth | Artificial intelligence | Present and emerging | Built around parallel processing, natural language processing and machine learning, aiming for machines that can reason and learn rather than simply execute fixed instructions. |
Classification of computers
By size
By type
By purpose
Converting between storage units
A branch's scanned-document archive is reported as 5,600 MB. Convert this to gigabytes, using 1 GB = 1,024 MB.
5,600 MB / 1,024 = 5.47 GB (to two decimal places).
The branch's own internet line is separately advertised at 320 kilobits per second (kbps). Since 1 byte = 8 bits, that is 320 / 8 = 40 kilobytes per second (KB/s), the unit that can actually be compared directly against a file size quoted in KB or MB.
Exam tip
'Hardware', 'software' and 'program' are the trio examiners most often blur together. Hardware is what you can touch; software is the full collection of programs, data and documentation that instructs it; a program is one specific set of instructions within a piece of software.
Self-check
(a) A document archive totals 2,560 MB. Convert this to gigabytes, using 1 GB = 1,024 MB. (3 marks)
(b) Distinguish between data and information, giving one example of each drawn from a shop's daily sales record. (4 marks)
(c) State the five elements of a computer system, and explain what happens to the system's usefulness if the 'people' element is missing while the other four remain intact. (5 marks)
(d) Distinguish between the third and fourth generations of computers, identifying the specific technological leap between them. (3 marks)
(e) Distinguish between a general purpose computer and a special purpose computer, giving one example of each. (4 marks)
Show worked answer
(a) 2,560 MB / 1,024 = 2.5 GB. (3 marks)
(b) Data is raw, unprocessed facts and figures that carry no meaning on their own, for example a raw list of individual sale amounts with no further detail attached. Information is data that has been processed, organised or structured so it is meaningful and useful, for example a daily sales summary report showing total revenue, best-selling item, and comparison against yesterday's total. (4 marks)
(c) Hardware, software, data, procedures, and people (users). If people (the users) are missing while the other four elements remain intact, the system has every physical and technical capability needed to function, but no one to actually enter data, operate it, or retrieve its output, a computer system with no one to use it produces no actual useful work despite being fully equipped to do so. (5 marks)
(d) The third generation was built on integrated circuits (ICs), many transistors etched onto a single chip, giving a jump in speed and reliability and the first use of operating systems, but a computer of this generation was still typically large. The fourth generation was built on microprocessors (VLSI), an entire processor fitted onto one single chip, the specific leap that made the personal computer possible, shrinking a machine that once filled a room down to something that could fit on a desk. (3 marks)
(e) A general purpose computer is designed to run many different kinds of program, from word processing to accounting to games, for example an ordinary desktop or laptop computer. A special purpose computer is built and programmed for one specific task only, for example the embedded computer that controls an ATM or a washing machine, unable to be repurposed for a different task the way a general purpose computer can. (4 marks)