Sunday, October 11, 2009

Hardware Requirements for Unix

From the Lilliputian system on the PDP-11, Unix has emerged to be a rugged stalwart today. There are some prerequisites for a system that can host and take best advantage of it. These are an 80 MB hard disk and at least 4 MB of RAM (Random Access Memory) on a 16-bit microprocessor (80286, or preferably 80386/80486). So you need a PC/AT or higher with the aforementioned configuration to employ Unix to the best of its ability. And how do we connect the terminals to the host machine? Through a 4/8/16 port controller card installed in the expansion slot on the mother board of the host machine. One end of the cable is plugged to the port on the controller card and another end to the serial port (9 pin or 25 pin) of the terminal. Any DOS based machine with a serial port can act as a terminal.

Out of 80 MB disk space almost 40 MB is eaten away by the actual Unix OS files whereas another 10-20 MB is used as swap space. The swap space is used when Unix falls short of memory. At such times it temporarily stores in this swap space the contents of memory which are not immediately required. Whenever these contents are required they are read back from the swap space.

More the number of terminals more should be the memory on the host machine. As a thumb rule we can say that per terminal to be supported 0.75 to 1 MB should be present in the host machine.

Besides the hardware, Unix also requires a considerable amount of human support. This comes in the form of a System Administrator who supervises the working of Unix on any installation.

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