Components of a computer
Facts about computers
The ram
Currently RAM is measured in megabytes and gigabytes. A typical computer system will have from 256MB to 4MB installed. The general rule of thumb is that the more memory you have installed the faster the system will be.
Most modern computer systems have the capacity for more RAM to be added up to a maximum. The maximum allowed and the particular type and specification of the RAM will be found in the manual for the motherboard.
Alan Turing
Touch screens
Tim Berners-Lee
Time Berners-Lee made the first communication between an HTTP (Hypertest Transfer Protocol) client and server through the internet in November 1989. He invented the World Wide Web.
He received a knighthood in 2004 from Queen Elizabeth II.
He is the director of the World Wide Web Consortium (W3C) a group set up to oversee the development of the World Wide Web.
He was honoured during the opening ceremony of the 2012 Summer Olympics in London.
He was born on 8th June 1955 in London.
In 2001, Tim Berners-Lee became a Fellow of the Royal Society.
He was a very keen trainspotter when he was a child and he enjoyed playing with model railways.
He has admitted that the pair of slashes (//) in web addresses ended up being unnecessary. He said he could have designed URLs without them, but didn’t realise at the time.
He was one of Time Magazine’s ‘100 Most Important People of the 20th Century’.
He is sometimes referred to as TimBL.
The four generations of a computer
The first Generation (1945 - 1955)
- Very large computers made up of vacuum tubes and often programmed using wiring plugboards
- Programmed using machine language
- Mostly used for numerical calculations as working out mathematical tables
- No OS
The Second Generation (1955 - 1965)
- Mainframes made up of transistors
- Mainframes made up of transistors
- At first punch cards were used to provide input, then tapes were used (for batch processing)
- Used Assemblers and FORTRAN compilers for program writing
-Simple batch processing was used with input files, programs and output on tape
- Smaller computers (e.g. IBM 1401) was used to read programs and data on punch cards on to input tapes and for offline printing
- Used mainly for scientific and engineering applications
- FMS () and IBM IBSYS as OSs for handling jobs (e.g. to read a job and to run it)
The Third Generation (1965 - 1980)
-Mainframes based on small scale ICs were used.
- Capable of multiprogramming (running several jobs at the same time)
- Fixed disks were used and new jobs on cards to be executed could be read on to the disk while executing other jobs (spooling)
- Though the first models used multiprogrammed batch processing, to cater to increased response time, timesharing was introduced later (Time-sharing Systems)
- Complex OSs as OS/360 were used.
- Used for various applications including scientific and business applications
- Mini computers also appeared on the market which were used by small departments etc. and became the platform for UNIX.
The Fourth Generation (1980 . . . )
- Mainframes, Minicomputers, Workstations, Personal Computers (Desktop and portable) based on VLSI components
- Network operating systems that facilitate file sharing, remote logging etc. and Client Server computing.
- Distributed OSs that make use of multiple machines and processors to run applications.
- GUI based OS interfaces and applications.
- Virtual Machines and Network Computers (NCs