Hardware Reference
In-Depth Information
1 The PC
Ever since IBM entered the personal computer scene, it was clear that its 'PC'
(first announced in 1981) would gain an immense following. In a specification
that now seems totally inadequate, the original PC had an 8088 processor, 64-
256 kilobyte (KB) of system board RAM (expandable to 640 KB with 384 KB
fitted in expansion slots). It supported two 360 KB floppy disk drives, an 80
columns
25 lines display, and 16 colours with an IBM colour graphics adapter.
The original PC was quickly followed by the PC-XT. This machine, an
improved PC, with a single 5¼ in. 360 KB floppy disk drive and a 10 megabyte
(MB) hard disk, was introduced in 1983. In 1984, the PC-XT was followed
by a yet further enhanced machine, the PC-AT (where XT and AT stood for
eXtended and Advanced Technology, respectively). The PC-AT used an 80286
microprocessor and catered for a 5¼ in. 1.2 MB floppy drive together with a
20 MB hard disk.
While IBM were blazing a trail, many other manufacturers were close behind.
The standards set by IBM attracted much interest from other manufacturers,
notable among whom were Compaq and Olivetti. These companies were not
merely content to produce machines with an identical specification but went on
to make further significant improvements. Other manufacturers were happy to
simply 'clone' the PC; indeed, one could be excused for thinking that the highest
Photo 1.1
Setting up a PC requires access to both hardware and software
