GIF.THD --- Copyright 1987 by Phil Wheeler An original compilation of Compuserve Model 100 Forum messages for use by Forum members only. Compuserve has introduced a new graphics protocol, GIF. Can it be used in the Model 100, et al? These messages report "progress" along these lines. Watch for futher developments. Message range: 154278 to 155319 Dates: 8/6/87 to 8/21/87 Sb: #GIF progress report: Fm: Neil Wick 71056,613 To: ALL First the good news. Important routines written in C have been translated to 8080 assembly language so there's no problem there. The bad news is that the expand suroutine uses a code table of 20-25K. Unless there is some more compact way of doing it the M100 RAM seems a little tight for space. I still hoping for a solution. Fm: Denny Thomas 76701,40 To: Neil Wick 71056,613 You might try contacting Traveling Software about the way they pack the Sardine dictionary. 30,000 words in 100,00 bytes. They certainly wouldn't disclose trade secrets, but you might get a good enough description of the theory to duplicate the process. Fm: Doug Pratt (ModelNet) 76703,3041 To: Neil Wick 71056,613 Could you make it happen by accessing the code table from, say, a Munk disk? (tongue hanging WAY out!) Fm: Neil Wick 71056,613 To: Denny Thomas 76701,40 It's been mentioned before that Sardine uses a method where only the different letters from the the previous word need to be stored. The GIF compressor already uses something of this sort. I don't think TS would give out any more details anyway. Fm: Neil Wick 71056,613 To: Doug Pratt (ModelNet) 76703,3041 I had thought about putting the code table on a DVI disk. The Munk may be harder since I don't have one, but I will certainly keep it in mind if I don't find a way to do it in RAM. I think the actual GIF file will have to be on some peripheral (Disk or Tape or maybe RAM bank) to give room for the program to operate. Fm: Doug Pratt (ModelNet) 76703,3041 To: Neil Wick 71056,613 Tape, huh? A classic example of Steam Radio! I like the idea of putting the file in another RAM bank. Lets us folks who can't afford the contiguous RAMs use the memory anyway. Any of the other options seem fine, and a real challenge to the programmer as well. Are you into challenges? I'm not, but they keep coming anyway. Fm: Neil Wick 71056,613 To: Doug Pratt (ModelNet) 76703,3041 I must admit I like challenges, but this may be just a little too challenging! Fm: James Yi 73327,1653 To: Neil Wick 71056,613 How about decoding the GIF file on line? That way the actual file doesn't have to be stored anywhere. Fm: Neil Wick 71056,613 To: James Yi 73327,1653 Online display is supposed to use CIS B protocol, so that's yet another consideration that I haven't really looked into yet. A binary download is really necessary if a file is to be downloaded, yet another thing that's never been done on the 100/102. Anyway, before considering any of this is the question of the code table. GIF files have up to 4028 codes. Current programs use 5 bytes per entry which equals 20140+ bytes of stack space, not to mention the program, etc. GIF was really designed with 16-bit computers in mind. I don't think any 8-bit programs are available yet (though some are in the works), and I don't think any computer has online viewing capabilities yet. Fm: Tony Anderson 76703,4062 To: Neil Wick 71056,613 There are a series of files in DL3 (5 to be exact) which support the CompuServe B protocol on the Model 100 - all named CISTRN, with different extensions. No compatible programs are available for the 200 or other computers supported here though. Binary downloads come in two flavors... the first is really just the extended ASCII character set, where the 8-th bit is included to allow characters between 128 and 255. Some files of this type have been available here, but usually causes such confusion among members who have their parameters set for 7-bit that we avoid it like the plague. It can be done, however, with proper training (or re-training) of the members. "True" binary uploads and downloads of tokenized BASIC files, and .CO programs is possible with the use of the commercial TELCOM enhancement program X-TEL. It is not in general usage, but the various members of the forum staff, and some members who are working on special projects, do use that capability. So if the GIF files require "True Binary", it is available, although not as a public-access program. Fm: Leonard Erickson 70465,203 To: Tony Anderson 76703,4062 Tony, I *wish* those files supported CIS B. They support CIS A protocol,which is older, and not useful for the advanced stuff. I've got docs on CIS B, but it is rather messy. *IF* anyone ever implemented it for the 100, you'd almost have to use external storage. Either that, or have the program in ROM. (Do you get the impression that I think it'd be big? Wrong, I suspect it would be *huge*!) CIS B on a Model 3 takes around 16k.... On the 100 it could be bigger. Fm: Tony Anderson 76703,4062 To: Leonard Erickson 70465,203 Now that's interesting... I didn't know that. Wonder where I got the idea that it supported B. Sorry about that, but you've added to my knowledge about it. Thanks. Fm: Mel Snyder 70136,1007 To: Denny Thomas 76701,40 The secret is the new method of daisy-chaining ROMs developed by PG Designs. See my submission SAFE.REV. Fm: Neil Wick 71056,613 To: Tony Anderson 76703,4062 It does need a "true" binary download in the sense that all ASCII codes from 0 to 255 can occur. Regular DO files can't have (0) or (26) or (127) in them. This problem even comes with some RLE files. Thoses encoded on the C64 usually contain (127) which is delete and do not download properly. My UR2 in View80 mode doesn't have these restrictions in download mode, which usually leads to a cold reset after certain illegal characters have been downloaded into DO files. I have an 8080 listing of CIS B, but I haven't had time to analyse it yet, so I don't know what the size restrictions are for sure. Fm: Phil Wheeler 71266,125 To: Neil Wick 71056,613 Neil, there has been some interest in the 8080 version of CIS-B. How can we get a copy? Would like to take a look!