80-Bus News

  

May-June 1984, Volume 3, Issue 3











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division didn’t exactly go a bundle on the “stuck up twits” in the computer division (their description, not mine). When we told the typewriter division just how unhelpful the computer lot were, the typewriter guys bent over backwards to provide all the stuff we needed.

More recently, a number of medium priced (500.00 to 600.00 price bracket), medium duty daisy wheel printers have become available, mostly from the Far East. Brother, the Japanese typewriter people (is it the same as the sewing machine and knitting machine company?) have a number of daisy wheel computer printers with or without keyboards in all price brackets except the very lowest. Of the Brother machines the best way to describe them is “average”, you seem to get what you pay for. None are exceptional for the price, but all seem to be provided with the facilities that you might expect from the competition at a similar price. Qume, Olivetti, Triumph Adler, Tec and many others have followed the lead with machines in this bracket. But these are still too expensive for the home and small business user.

The Juki 6100 (I might have the number wrong, but the one you can get for about 300.00) is a very nice machine. Not fast, but a well built mechanism and very precise character registration. The only thing I don’t like is the choice of wheels and ribbons. Now I’m all for standardisation is this area. I recently came across a -Kores” printer ribbon catalogue (trade bible), and there are about 600 different types of cassette ribbon in the catalogue. About half of these are visually similar, but bet your bottom dollar, a ribbon for one machine which looks almost like a ribbon for another won’t fit. The same applies to daisy wheels, there is a bit more standardisation here, put a growing trend for each printer manufacturer to make his own unique wheel for his printer. Like I says, the Juki have chosen Triumph Adler wheels and ribbons for their printer. On the face of it a very sensible idea, as these are the wheels and ribbons used by the Triumph Adler office typewriters, and so, should be available at your local stationers. Well I tried our local branch of a big chain stationer, and yes, they had them. The snag? The price. 6.00 for a ribbon and 22.00 for an ordinary plastic daisy wheel. Ll tried the local Indian stationers, he was a bit cheaper for the ribbons, 5.50, but didn’t have the wheels. What a rip-offt!.

Two daisy wheel printers have recently come under my scrutinization, and having given then an intense scrute, [ will now pronounce myself!! The Sanple Daisy Step 2000 and the almost identical (but not quite) Quen-Data printer. Both printers cost about 225.00 and both are Qume clones in ali but speed ami quality of construction. Actually, Quen might just be a Far Eastern misspelling for Qume, who knows. Anyway, both use Qume wheels, which are cheap at about 5.50 to 6.00. and available in a vast range of type styles and pitches (if you can only find someone who actually keeps more than just a couple of types), and the carbon multistrike ribbons are cheap at about 3.00 and seem to last for ever.

Both printers have a Centronics interface with a 256 character buffer. The Sanple has a serial RS232 option at about 55.00 with a 2K buffer. The Quen probably has a serial option available, but I haven’t yet discovered for sure or how much. The printer control protocols are a superset of the Qume Sprint 5, and being a superset have a few extras thrown in, for example software selectable bidirectional logic seeking printing, selectable hammer strike pressure, etc. Printing speeds are about 20 characters per second with high speed skipping of white space. All the internal software seems to work without bugs, and although slow, the print output is of very good quality.

What about the mechanism? Well it’s Ok so long as you keep the lid shut and don’t look too closely. Pressed steel chassis, guides and runners where the Qume has a diecast aluminium chassis and precision ground steel guides and runners. The carriage is poorly located on the guides with nylon carriage slides. By contrast the Qume has phosphor bronze bushings for the front guides and sprung ball races for the rear. A not so subtle difference between the Qume mechanism on the one hand, and the Sanple and Quen on the other. Mind you the price difference isn’t so subtle either, the Qume costs nearly ten times as much as the other two.

The point is that both these cheap printers work, and work well. There can be no doubt that they won’t stay working as long as the Qume, but then in a home environment, that sort of longevity isn’t required. These two are DRH’s best buy at the moment.

And so on to other things

I’ve spent some time doing some late spring cleaning amongst my disks and in the process came across a nice little program by Ward Christensen. Now for those who aren’t devotees of the various CP/M User Groups, Ward Christensen is a software writer of some renown and greater output. You could be forgiven for thinking that he has single handedly written all the software on all the couple of hundred US CP/M User Group disks. He hasnt, but his name must certainly appear more often than most. Anyway, SCRAMBLE isa neat little encryption program for scrambling the text or code of a disk file. I liked the program so I spent a little time doing a little tidy here and a little tidy there just to provide fodder for those who like to find DRH’s deliberate mistakes. Now I’1ll not take the blame for all the mistakes, only the ones I’ve committed, as the source code came to me as a Z80 source program. Now I haven’t yet seen a Ward Christensen program written in Z80, it’s always 8080 assembler, so someone has translated the file, and possibly done goodness knows what else in the process. So with no more said, Ill re-print Ward’s original DOC file here, and the source will appear somewhere else in this mag.

"SCRAMBLE is a command used to encode a CP/M f’

The format of the command is: “SCRAMBLE filename.type password" where “password” is an 8 character password made of characters permissible in a file name (i.e. no ".", etc). To obtain a good “initial seed" for the scrambling process, no character in the password may appear more than twice.

The requested file is scrambled, and re-written in place. To unscramble the file, the IDENTICAL command is issued, i.e:

>SCRAMBLE filename.type password This is because SCRAMBLE does an “exclusive-or" type modification to the file, and doing two identical exclusiveors to data result in the same data being returned.

I feel a scrambled file is quite secure. Given that a file was scrambled and the password forgotten, I know of no way to determine what the original file was. Even a file which is all binary-0’s, is sufficiently scrambled to defy finding out what the password or original data was. ...But Il assume no responsibility for the "security" of files scrambled with SCRAMBLE as I am not a "student of cryptology".

Note also, that if an attempt is made to unscramble a scrambled file, using the WRONG password, then the file ie technically “double scrambled" and SCRAMBLE would then have to be executed TWICE, once with the original password, and once with the erroniously-used password. Because of the exclusive or-ing process, either password may be used either time.

03/11/79 Ward Christensen"

Comms Software

Following Ward*s Scramble, I’ve had a letter from Arto Liimatta in Finland, who has thrown all the beautiful and complicated “comms software out of the window and come up with a very simple patch to PIP.COM to make it communicate with another PIP on another machine, suggested by an article in "Microsystems" July 1983. As he writes,

"TY also put here one program PIP, and how to use it for transfering data between maschines. It uses some kind of handshaking in the transmitting procedure, so the receiving maschine won’t lost data, while it is saving it to disk. The transmitting computer sends a character and when the receiving computer gets it, it echoes it back to the transmitter who then knows the receiver is ready. When the receiver is not ready it does not echo until it is ready to receive. I think it has been used for many years, but I haven’t seen it yet in 80-BUS News."


This is an OCR’d version of the scanned page and likely contains recognition errors.











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