I've been trying to trace out the early history of Forth implementations on the 6502.

From this brief overview and other sources, it seems that Robert Selzer and Bill Ragsdale might have been first, with a commercial Forth, for the Jolt kit machine.

Bill tells the story here that he got the very first Jolt in 1976.

In a much later interview here (pdf, page 20) Bill tells how he tidied up version 3.6 of that commercial Forth and released it into the public domain to form the basis of FIG Forth. Sounds like that would be '79. This was in response to two things: FORTH Inc saying that they wouldn't be doing a Forth for personal computers, and there being a PET Forth which was "terrible".

Based on that 6502 version, and with enhancements from the University of Utrecht, FIG organised a set of pairs of programmers to write versions of Forth for several processors, using the same spec and the same labels (in the same order). That was to be a "Rosetta stone" for FIG Forth.

Comments and corrections welcome!

Cheers
Ed

Edit to add: Forth Inc's history says it was in 1978 that Ragsdale and Seltzer wrote their Forth for Jolt, subsequently to asking Forth Inc to write one for 6502.

I think it's interesting that Seltzer had previously written for 6800. People in that position might be able to comment on the differences - perhaps, advantages and improvements - of the 6502.

Thanks, Ed. Here are a few dates from printed documents in my possession.

• June, 1980 - 6809 Fig-Forth Assembly Source listing release 1 v1.0
  
• Sept, 1980 - Fig-Forth 6502 Assembly Source listing release 1.1
  
• Nov, 1980 - Fig-Forth Installation Manual; Glossary; Model; Editor. Release 1
  
• Oct, 1983 - Fig-Forth 68000 Assembly Source listing release 1.1

In addition to 6502 Fig-Forth, I also used Bill Ragsdale's RPN style 6502 assembler (which is written in Forth, of course). The contribution he and his colleagues made is enormous.

-- Jeff

Thanks Jeff!

I notice our own chitselb has written a new Forth for PET and was previously casting around on comp.sys.cbm for an earlier PET forth - perhaps the "terrible" one. That thread contains a similar history to what I found - hopefully coherent with my findings.

Cheers
Ed

When I was researching it just over 20 years ago at work, the small performance difference I came up with was that the 6502 FIG Forth ran about 25% faster than the 6800 FIG Forth at a given clock speed.

Thanks for the datapoint!

Edit to add: Found a quote from back in 2001, when you said:

along with other interesting commentary

What I really want to know is how did early 6502 Forth implement virtual memory on cassette tape? My approach is to use the PET sequential file (192-byte blocks) and simply copy from one deck to the other. Slow, cumbersome. It would probably be easier to use the file system and load/save chunks of source code as text files, but less Forth-like

I would imagine people were hooking up floppy drives, although I could be wrong. In the UK floppies were very late to arrive. I was reminded of the Hobbit tape drive which uses microcassettes and crucially can be controlled by the host. I don't know if it was UK only or when it appeared. Here's a feature from 1983 (pdf)
http://acorn.chriswhy.co.uk/docs/Mags/A ... Hobbit.pdf
but I would have said it dates from the 70s.
Cheers
Ed

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Ah, here we go: the Hobbit for the NASCOM - aka UltraDrive, but same manufacturer (Ikon)



Hmm, but also same year - 1983/1984 (seems a bit late for a NASCOM) - I would have said I saw advertisements in the late 70s for some kind of automated-transport tape-based data storage system.

(Not to confuse these systems with tape-loop systems.)

Interesting point about the lack of capstan. Also, I see the HP unit is also 1980's vintage: see this PDF
http://www.hpmuseum.net/pdf/KeyNotes_19 ... es_OCR.pdf

Edit: replaced links to broken site with links to a different site.

anyone has schematic of this kind of storage things ?

You might need to ask very widely to find someone with a schematic: the cctalk mailing list would be one additional place to ask. There are very active forums for Atari and Commodore machines, but neither of those machines would be likely to need a drive like this - even so, some of the people there might have an idea. (Similarly the cbm-hackers mailing list, and any number of retro-machine Usenet groups.) Another possibility is to mail as many computer museums as you can find.
Good luck!
Ed

BITD, working on Alpha Micros, they backed up to VHS tapes using VCRs much like we used to use cassette tapes. Later, they were early adopters of Exabyte drives, which used Betamax tapes.

The games with these micro-cassette drives (or similar things) is fast tape speed and a sensor to capture partitions on the tape (file start/stop, etc.).

One of the devices mentioned above talked about 30sec rewind times and "average" file seek time of 13 second (which is suspiciously close to half the time to rewind the tape). With an adequate driver that "knows" where it is on the tape, the system can know whether to go forward or back to find a specific entry.

But the dark side is how to write data to the tape and not overwrite other chunks. I've heard of systems that would "format" tapes, and I guess in the end it's not much different from a floppy disk, just with sequential access. I don't know if there was much need for tolerances based on tape speed or stretch. I assume you can position the tape with reasonable precision.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Eureka! I have found it! There were hints on the volksForth pages about it also running on a PET, but I haven't been able to find a binary copy of volksForth for PET. Most of my experience comes from Blazin' Forth on a C=64 and MMSForth on a TRS-80 Model 4. However, now I do have this Fig Forth 1.0, and in fact, this is the first running Forth I have ever used on a PET. Cassette support is definitely a thing here.

It comes up and says "FIG FORTH 1.0" and it even uses the Commodore zeropage CHRGET routine at $0070-$0087, as well as making a copy of stuff that BASIC wants to have around (as part of the cold start routine.) Hopping in and out of Forth/TIM/BASIC works. I haven't yet figured out the setup steps required for using BLOCK with the disk ('2 BLOCK' returns $C9FD, an address in ROM. '3 BLOCK' hangs the machine).

So I'm in there digging around trying to figure out what does what. Here are tick ( ' ) addresses of a few words I'm interested in and some early findings. To get around the problem of the Commodore tape i/o routines failing out to a BASIC READY prompt, it seems that the authors of this Forth could have just restored BASIC pointers prior to doing any *dangerous* operations. But it is late, I am lazy, and manually decompiling secondaries is tedious, so I do not know this for sure. It is pretty clear that this Forth doesn't use BLOCK with the tapes, and probably no commie Forth ever did, but it does provide words for save/load operations.