portion is in memory, but if you keep moving up and down the file the delays
become painful. But if the text file is on a virtual disk, then WORDSTAR
continues to be fast, even with vast files. Another example is the amazing VIZAPL
which is a full implementation of APL for microcomputers. It is available for the
which displays all the APL characters very beautifully. VIZAPL has
the amazing ability to extend real memory using its own virtual memory technique
to move little used data and procedures to disk. If the virtual workspace is put
on to the virtual disk, then the speed improvement with large APL workspaces is
very impressive. It is like having the memory addressing capability of a 16 bit
microcomputer, but on an 8 bit Z80.
To summarise the advantages:–
- high performance exceeding that of any real disk, whether floppy or hard;
- no disk wear or noise in operation;
- ideal with CP/M if CCPZ used, and for SUBMIT operations if it is drive A;
- special benefits with some software such as WORDSTAR and VIZAPL.
And the disadvantages:–
- more expensive than real disks – but this is getting better;
- a power cut can be a disaster if you run for hours without backup;
- it can be boring moving files to and from the virtual disk.
So are virtual disks useless? No.
E.V. BEEPER – A MINI-REVIEW
by RICHARD BEAL
Recently I was using a conventional CP/M system (a Rair Black Box) and I
found that it had a feature that I wanted (apart from a hard disk). To be
accurate, the terminal had the feature, not the computer. It went BEEP. I hadn’t
realised that various bits of CP/M software go BEEP to warn you of things, and of
course it is very easy to put
into a BASIC program. All you need is a beeper. I found that one already existed,
from E.V. COMPUTING LTD. I have a Gemini intelligent video card
already supports a beeper by putting out a signal when it receives a Control/G
(07H). The beeper detects this signal and goes BEEP. I ordered the beeper by
phone, using a credit card, and the beeper arrived all the way from Manchester
the next morning. Ten minutes later, with the help of very clear instructions, it
was working perfectly. I had a nasty fright when I turned the machine on, because
it went BEEP at once. In fact it now always goes BEEP whenever it is turned on or
off. The BEEP is really more like a choked warble, and the manual describes how
to modify the beeper to make it warble differently.
The instructions explain how it can also be used if you do not have an IVC,
using a signal from the Nascom keyboard port. This requires some extra software
to be patched in, and this would need a bit of work by the user, but it is well
documented in the instructions.
I recommend this product, which works perfectly, for those who want a simple
beeper. It does not play music or sing, but it is very reasonably priced at
£12.50 plus VAT.
E.V. COMPUTING LTD., ___ _______ ____, BURNAGE, MANCHESTER ___ ___.
Tel. ___-___ ____