Electron User1st September 1987
Published in Electron User 4.12
Roland Waddilove assesses a 64K printer buffer designed to increase your micro's efficiency
All Good Stuff...
Have you ever sat twiddling your thumbs while waiting for the printer to produce a long document or listing? Well, MicroStuffer is designed to avoid this holdup altogether by providing a massive 64K printer buffer.
One problem of using a computer with a printer is that they both run at different speeds.
Computers like the Electron process information at quite a high speed, yet printers can only print the data provided by the micro relatively slowly. This forces the micro to reduce its speed to match that of the printer.
The effect of this is apparent when printing long documents or screen dumps - the micro is tied up for several minutes while the printer clatters away, preventing you from getting on with your work. To make matters worse, the better the print quality, the slower the printer runs and the longer the micro is tied up.
This is why many printers, and even some software packages, have a draft and final quality print mode.
If you want a rough idea of what the document looks like on paper, you use draft mode for speed. When everything is to your liking you use final quality - which may take up to twice as long to print, but the finished article is much more presentable.
A printer normally has a very small amount of RAM on-board, typically 1K or so, which it uses as a buffer. When it is empty, a signal is sent to the micro telling it to send some text.
The micro sends characters until the printer signals the buffer is full and waits for it to print the text.
When the buffer is empty again the printer requests more text from the micro.
It sends this so quickly the buffer fills in no time at all and consequently spends most of its time waiting for the printer to empty it. This time is wasted as the micro can't be used for anything else.
The larger the printer's buffer, the more text the micro can dump in it before it becomes full. If it is very large, say 64K as in the MicroStuffer, the whole of the text will easily fit in.
The micro dumps all the text in the buffer and you can start on your next task straight away.
The printer will print all the text in the buffer regardless of what the computer is doing (in fact, you can even switch it off) so you can get on with the rest of your work.
So this is the idea behind the MicroStuffer - a large buffer is added between the computer and printer and the micro dumps all the output in it.
The printer prints while the micro is free to process the next document, screen dump or report.
The unit is small, unobtrusive and can be tucked away in a corner of the desk. It comes complete with its own power supply.
The socket on the back of the cream-coloured case is identical to the one on the printer and this is where you plug in your printer lead. A short cable runs to a plug which fits into the printer's socket.
All you do is plug in, switch on and it's ready to go - it couldn't be simpler. In fact, you won't notice it's there - except for the time saved.
There is an on/off switch plus two buttons on the front of the unit. One is a repeat button which reprints the contents of the buffer and the other is a panic button.
If you fill the buffer with text and suddenly discover an error, you can hit the Clear button and flush it. You can't do this from the computer.
MicroStuffer isn't cheap, but if you find your time is being wasted waiting around for the printer, it could improve your efficiency no end.
If you rarely use your printer it isn't necessary, but if you regularly print large documents it could repay itself in time saved very quickly.
It isn't micro-specific and will work with any computer and printer combination with Centronics-type ports.