Conventional Information Pyramid

IT Information Pyramid

Mini Glossary - Some IT Hardware Jargon

Bit: All computers work in what is known as "binary" arithmetic. This means they reduce everything to strings of noughts and ones. Each nought or one is called a "bit" (the word comes from shortening the separate words "binary digit"), and the capacity of much of the hardware is measured in the number of bits it can (a) store, and/or (b) transmit per second. The common units are kilobits (Kbit), which are thousands of bits, and megabits (Mb or Mbit), which are millions of bits.

Byte: Bit strings are useful, but do not actually mean a great deal to the person in the street. S/he wants to see readable English. What the hardware does, therefore, is to allocate different 8-bit strings to each of the letters of the alphabet (as well as the numbers and the punctuation marks). This is very clever on its part, because it can then talk your language and its own at the same time. Each of these 8-bit strings is called a byte, although the equivalent terms character or keystroke are also regularly encountered. The common units are kilobytes (KB, or KByte), which are thousands of bytes, megabytes (MB or MByte), which are millions of bytes, gigabytes (GByte), which are billions of bytes, and terabytes (TByte), which are trillions of bytes. Since a byte is eight times the size of a bit, you should take care not to confuse Kbit and KByte, etc.

CPU: This stands for central processing unit. Functionally, it is where the machine does its thinking, and physically it is a microscopic logic circuit, capable of switching binary electric pulses according to an internal binary electric state. And you can control that processing by giving it additional pulses - "instruction" pulses - which change its internal state. This is also very clever on its part, because it gives the ability to redirect pulses on demand between RAM, filestore, and peripherals. The logic circuit is mounted on/built into a tiny sliver of silicon known as a silicon chip or microchip.

Filestore: The problem with RAM is that its contents are lost as soon as the power goes off. More permanent storage is provided by disk drives. There are two types of disk drive, namely (a) the floppy disk drive, and (b) the hard disk drive. They are both magnetic media, that is to say, they record by creating magnetic images of the electrical noughts and ones on a magnetic coating, and they read back by reconverting the magnetism back into electric pulses. (In this respect they work just like audio and video tape.) Modern floppy disks (or "diskettes") are 3.5" diameter disks of magnetic medium contained in a plastic safety sheath, and typically hold 1.4 MByte of data. Hard disk drives contain anything from 10 MByte to 10 GByte or more, depending on how old and/or expensive the machine in question is. Floppy disks can be removed from the machine for transport and/or safe keeping, whilst hard disks are built into it.

Instruction: A binary control code capable of causing the CPU to act in some predetermined way on the data stored momentarily within it. (See extended definition in the glossary in next lesson.)

Laptop: A portable microcomputer.

Mainframe: Mainframes are large computers. They need their own air-conditioned building, with full security systems and highly trained operating and support staff. Mainframe systems were very much the rule until the arrival of microcomputers in the 1980s. Since that time, however, microcomputers (both standalone and networked) have made continuing inroads into the mainframe market. Opinions differ as to the long-term prospects for mainframes. Some theorists say they will eventually die out altogether; others disagree.

Microcomputer: Microcomputers (or "micros") are small and relatively inexpensive computers built around one or more powerful microchip processors. They are sometimes referred to generically as "PCs", which is an abbreviation of "personal computers", and can be "standalone" or "networked", depending on whether they are linked to other microcomputers via a network, and "desktop" or "laptop", depending on whether they are intended to be portable.

Network: Great advances were made in the 1990s linking microcomputers together into networks. The most commonly encountered network is a LAN (short for local area network). LANs typically consist of up to 30 or so microcomputers, linked together via cables and sockets, and controlled by a central machine called a file server (or, for short, just server). A standalone microcomputer can be turned into a networked one simply by fitting it with an additional module containing the cable socket mounting and the necessary additional circuitry, and loading it up with additional software called netware. The netware on the microcomputer then "talks to" the netware on the server to manage the technical aspects of message handling around the network, and you, the user, are free to talk to as many or as few of the other network users as you wish.

Peripherals: Items of hardware - screen, keyboard, mouse, printer, scanner, etc. - attached to your CPU.

RAM: This stands for random access memory. It is a microchip memory circuit, that is to say, an electronic circuit capable of temporarily storing binary electric pulses. It contains the machine's current state of mind, as it were, and its capacity is an expression of how powerful your computer is. Both data and code can be stored in RAM, but only until the next power-down. Each byte of RAM has its own address so that the CPU can access it precisely. Modern microcomputers commonly have 128 MByte of RAM.

ROM: This stands for read only memory. Like RAM, ROM, too, is a memory circuit, but its contents have been "sealed in", so to speak. This allows ROM chips to be loaded at the factory, without risk of loss of contents due to subsequent misuse or power failure. Essential software is often delivered in this form. The term CD-ROM is also encountered. This is the hi-fi world's five-inch compact disk transported for use in computer systems because it provides very large storage capacities (typically 600 MByte) very cheaply.

Server: A heavy duty microcomputer used to administer a network of smaller microcomputers, and requiring, by virtue of the sensitivity of this role, the same level of management and protection as a mainframe.

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EXERCISES (AND STANDARD STUDY TIMES): Depending on how thoroughly you have been exploring the hyperlinks provided, it has probably taken you less than 30 minutes to read the foregoing text, and now you have to do some real work. Complete the following exercises, taking careful note of the expected study times:

IT1.3.1

Imagine that you are a computer keyboard designer. State the binary word length necessary to allocate different codes to 26 upper-case letters, 26 lower-case letters, 10 digits, and 20 miscellaneous punctuation marks. What is the data transmission rate in bits per second between keyboard and CPU when you are typing 180 keystrokes per minute? [30 minutes.]

IT1.3.2

Ask your IT departmental contact to explain the terms "clock speed", "MIPS", and "Megahertz". [30 minutes.]

Submitting Exercises for Assessment and Feedback (Fee-Paying Clients Only): Simply e-mail your answer(s) for full tutorial feedback. State each conclusion clearly, and briefly explain how you arrived at it. You may do this one exercise at a time, or all at once. Additional questions may then be asked, and additional tasks given as required. [Submit an Exercise] Please cooperate with this student-tutor exchange, because it will eventually form the basis of your individual student progress record. Do not proceed to Lesson IT1.4 until all the tutorial tasks are completed and signed off.

Mini Glossary - Some IT Data Jargon

Batch Processing: Batch processing is computing done when it is convenient for the computer to do it (and, by the same token, it is computing which the user is happy to wait a few hours for). Batch processing is popular because it can be very efficient in terms of machine time to process lots of the same type of input all at once. Thus a thousand on-line requests for bank statements, for example, will merely be "batched up" and processed all at once at end of day.

Editing: The process of copying a file from one location in filestore to another, carrying out your changes (be they insertions or deletions) on the way. One very common use of editing is the creation of text files in word processing. This web file, for example, was edited many times before being photocopied. In the very first edit the file was created empty and a page or two typed in. In subsequent edits, a few pages were added at a time. Then, towards the end of the process, a lot of text shuffling and error correction took place. The overall process took some three months.

Editing, Tricks of: There are several useful editing "tricks" allowing blocks of text to be deleted, moved, and even duplicated on demand. Expert editors can jump around in this fashion at high speed, taking blocks of text from all over the place - including from more than one input file. The general rule is that if ever you find yourself typing in something you have ever typed in elsewhere, you are time-wasting. Far better to track down the material in question and block-copy it in instead. It is good practice to develop a strict discipline when editing, and then never to stray from it. This might even include shutting yourself away from sources of interruption such as the phone. You should also save your edit every few minutes in order to protect yourself against power failure (your latest changes are held in RAM and are therefore vulnerable in this respect). And, above all, you should back up your files onto floppy disk to protect yourself against accidental loss or corruption of the originals.

File: See main text, and the separate entries for index file, master file, reference file, and transactions file.

Index File: A file which links key fields to the disk addresses of the corresponding records, thus enabling rapid look up of the whereabouts of a particular record.

Instruction: A software code. A bit sequence which when input to a CPU can alter its internal state. This allows the CPU to move data from point to point and, if necessary, operate upon it as necessary as it passes, which, one way or another, is the basic operation in all computing.

Instruction Set: The repertoire of instructions recognised by a given design of CPU.

Master File: These are long term stores of detailed departmental data. They are the main files maintained by the system in question, such as a bank's records of its customers, an organisation's records of its employees, or a warehouse's records of its contents. Master files like these tend to be heavily accessed during a typical day's business, but because it is unpredictable just which record is going to be needed next they will have been stored in such a way as to allow what is known as "random access". This may or may not involve an associated index file.

On Line Processing: On line processing is computing "while you wait", such as asking for your bank balance, looking for holiday availability, booking theatre tickets, or checking the warehouse/ stockroom location of a stores item. The point is that you need to know what the situation is right then and there, and the idea is that you are put "on line" to the CPU, and have it working on your problem (but not necessarily on your problem alone) as fast as it can. There will frequently be minor delays as the CPU shares its time around several concurrent processing demands. Each distinct interaction with the CPU is commonly known as a transaction, and so on line processing is often termed (on-line) transaction processing. The terms demand processing and foreground processing are also encountered, as well as the abbreviations TP or OLTP.

"Real Time" Processing: This is processing which totally dedicates the CPU to you for the duration of a transaction. This contrasts subtly with the "high priority" access to the CPU given by on line processing. It is processing which simply cannot go any faster unless you buy more powerful hardware or write more efficient programs. Real time processing is therefore ideal for a variety of non-clerical computing tasks. The military and aerospace worlds, for example, are full of it. It is also creeping into the world of healthcare in such life or death areas as patient monitoring and the automatic administration of anaesthetics. Real time systems, however, are a highly technical specialism into which students should not venture unaccompanied.

Reference File: A file containing what is known as "look-up" data rather than transaction or master file data. The value of reference files is that they allow data to be omitted from master file transactions, thus saving space. When details are needed, they are simply "looked up". Compared to master files, reference file data changes much less frequently.

Transaction: A single distinct interaction between user and CPU (eg. a withdrawal of money from the bank). A logical unit of processing.

Transactions File: This is a file of accumulated operational level data (ie. individual transactions), in readiness for batch processing to update a master file (not needed, of course, for updates carried out on line).

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EXERCISES (AND STANDARD STUDY TIMES): Depending on how thoroughly you have been exploring the hyperlinks provided, it has probably taken you less than 30 minutes to read the foregoing text, and now you have to do some real work. Complete the following exercises, taking careful note of the expected study times:

IT1.4.1

Photocopy your latest telephone bill, highlight every data field thereon, and state for each what type of data is contained. Which (if any) is/are the key field(s)? Count how many keystrokes to store away all the data on one such form. Calculate how many megabytes of filestore would be required to store 6,000,000 such completed records reasonably safely. How might you name the resulting computer file?

IT1.4.2

Research the ASCII coding system, listing the binary codes it has allocated to the characters "A", "a", "8", "*", and space. Give your answers as both binary AND decimal numbers. How many bits in the word "bit"?

Submitting Exercises for Assessment and Feedback (Fee-Paying Clients Only): Simply e-mail your answer(s) for full tutorial feedback. State each conclusion clearly, and briefly explain how you arrived at it. You may do this one exercise at a time, or all at once. Additional questions may then be asked, and additional tasks given as required. [Submit an Exercise] Please cooperate with this student-tutor exchange, because it will eventually form the basis of your individual student progress record. Do not proceed to Lesson IT1.5 until all the tutorial tasks are completed and signed off.

Mini Glossary - Some IT Software Jargon

Compiler: The principle component of a programming package. A program capable of reading in source code and generating object code.

Database (DB): This is software which manages large stocks of data for you. The proper title of this sort of software is database management system (DBMS). Databases are the computer equivalent of the old-fashioned file index systems, but with the advantage of very rapid search times. These searches can also be totally adhoc: you might want to see all patients between the ages of 30 and 35 years, female, one-legged, and right-handed, and provided your master file has been set up properly you can phrase your enquiry in near-English using the structured query language (SQL) supplied as part of the DBMS.

Graphics Package: This is software which draws pictures, flow diagrams, graphs, pie-charts, etc. for you.

Machine Code: See object code.

Object Code: (Alternatively, machine code.) A sequential set of machine instructions. A program in machine-readable form as produced by a compiler. (Compare source code.)

Programming Package: A combination of editor and compiler, which allows source code programs to be written to solve business problems, and then converted into executable object code for implementation.

Caution: Packages are not systems. Packages are application software, but not application systems. They are simply tools for you to use. (You might well write applications using those tools, but that is a matter of choice and skill, and not many purchasers actually do so.)

Source Code: A program in human-readable form as input to a compiler. (Compare object code.)

Spreadsheets: A software package which manages text and numeric arrays. It is a very powerful tool for preparing (or rather helping you prepare) simple financial and statistical returns, although you will need to give considerable thought to where you will be getting the information from.

Structured Query Language (SQL): Generically, a repertoire of near-English instructions by means of which ad hoc enquiries can be made of a database. Also the name of a specific product which does this [for details of which, click here].

Word Processing Package (WP): Software which manages text.

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EXERCISES (AND STANDARD STUDY TIMES): Depending on how thoroughly you have been exploring the hyperlinks provided, it has probably taken you less than 30 minutes to read the foregoing text, and now you have to do some real work. Complete the following exercises, taking careful note of the expected study times:

IT1.5.1

Access the "Computer Weekly" electronic archives, and enquire using the keyword "Killer App". [30 minutes.]

IT1.5.2

Get your IT department, contact to explain the difference between "systems programmers" and "applications programmers". [30 minutes.]

Submitting Exercises for Assessment and Feedback (Fee-Paying Clients Only): Simply e-mail your answer(s) for full tutorial feedback. State each conclusion clearly, and briefly explain how you arrived at it. You may do this one exercise at a time, or all at once. Additional questions may then be asked, and additional tasks given as required. [Submit an Exercise] Please cooperate with this student-tutor exchange, because it will eventually form the basis of your individual student progress record. Do not proceed until all the tutorial tasks are completed and signed off.