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Cromemco Multi-User BASIC.

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    Cromemco Multi-User BASIC.

    Has anyone seen or (even better still) got a copy of the software and/or User Manual for the Cromemco MULTI-USER BASIC by any chance?

    Tried all of the usual websites...

    Dave

    #2
    I probably haven't the software (although I'll have a hunt) but I have a manual to be going on with however it busts the upload limit here as it is 1.7Mb. Any suggestions?

    James

    Comment


      #3
      Hi,

      Thanks for responding.

      I partially received your PM. The email I received as a result of your post contained the initial partial contents of your message. But, when I tried to inspect your message from within VCFED it was blank. For the mods. this may help them try and identify why some messages are appearing blank and others not? It is interesting that I received part of the message in my email though.

      I don't post things to VCFED because of the size limit. In addition, VCFED is not really a platform for disseminating this type of information.

      What I do is to scan a document, store it on my Google drive (other platforms are available) and send the Documentation Wizard (Al Kossow) an email with a link. Al will then "hoover it up" and put it onto Bitsavers for posterity and the benefit of the the vintage computer community.

      Thanks in advance for sharing.

      Are you "into" Cromemco computers by any chance? It is interesting to find quite a few people within the UK with a knowledge of Cromemco machines.

      Dave

      Comment


        #4
        You can PM them offline and email them directly, you can use a file sharing service such as Google Drive (if you have GMail) or DropBox. Most of the cloud providers offer similar file sharing things. No reason to host it in perpetuity.

        What were the standout features that made this a "Multi-User BASIC"?

        Comment


          #5
          As far as I can tell from the information I have found, the MULTIUSER-BASIC (along with the integrated Disk Operating System) lived in the top 32K of the Z80 memory space.

          The lower 32K of the memory space was bank switched (using the bank switch facilities of the Cromemco 16KZ and 64KZ memory boards) to support a separate memory space for each "user". I believe one lower block of memory was still required for the 'system'?

          Each user had their own terminal.

          I believe the BASIC must have some form of scheduler to switch between users and that various BASIC commands can be configured to prevent some 'users' from affecting the 'system' and other users. The BASIC must have come with the usual commands (PEEK, POKE etc.) that could have major undesirable repercussions within a multi-user environment... The ability for the system manager to deconfigure these types of commands would be a major positive - certainly in a business setting.

          I am not sure how many users the BASIC supports or anything else (hence the interest in the manual and software).

          Dave

          Comment


            #6
            Originally posted by daver2 View Post

            Are you "into" Cromemco computers by any chance? It is interesting to find quite a few people within the UK with a knowledge of Cromemco machines.

            Dave
            I am. I had a Z2-D long ago. Wish I still had it. Oh well. So enjoying reading about some threads here about it.
            PDP-8 and PDP-11 enthusiast. But enjoy most older PC stuff too.

            Comment


              #7
              Originally posted by daver2 View Post
              As far as I can tell from the information I have found, the MULTIUSER-BASIC (along with the integrated Disk Operating System) lived in the top 32K of the Z80 memory space.

              The lower 32K of the memory space was bank switched (using the bank switch facilities of the Cromemco 16KZ and 64KZ memory boards) to support a separate memory space for each "user". I believe one lower block of memory was still required for the 'system'?

              Each user had their own terminal.

              I believe the BASIC must have some form of scheduler to switch between users and that various BASIC commands can be configured to prevent some 'users' from affecting the 'system' and other users. The BASIC must have come with the usual commands (PEEK, POKE etc.) that could have major undesirable repercussions within a multi-user environment... The ability for the system manager to deconfigure these types of commands would be a major positive - certainly in a business setting.

              I am not sure how many users the BASIC supports or anything else (hence the interest in the manual and software).
              That sounds pretty good. That could go a long way, especially if they can allocate 16K or 32k to users. (thus potentially support 2 users in a single 32K bank). Without having to host the actual BASIC runtime, 16K of code and data is not nothing.

              The scheduler would be straight forward. Its true mechanic would be the bank switching, it would actually be really fast. Everything else "local" is constrained to the bank, at least at a BASIC level. The OS level may have different issues. But that can be managed by relying on a YIELD concept vs a timer interrupt. The YIELD being that a process gives up its "time" when it's safe to do so, rather than having the rug yanked beneath it like a time slicer.

              Since it's an interpreter (I assume), the Yield can be foundational within the interpreter loop, so even "CPU Heavy" code can potentially yield safely, vs having it all done at I/O points and having the BASIC code have to yield on its own. (Yielding on I/O is very common, early Windows did their yield within the main event loop while looking for mouse clicks, for example.)

              I find the idea of "multi-user" BASICs rather fascinating. That is, something where the BASIC runtime is the kernel, rather than the underlying OS. (To contrast it to something like, say, DEC RSTS which where BASIC was a first class citizen, but it was still subservient to the underlying kernel).

              Multi-User FORTHs are very similar in concept.

              Comment


                #8
                See page 54 (PDF page 7) of https://deramp.com/downloads/mfe_arc...20Software.pdf for the sales blurb...

                Dave

                Comment


                  #9
                  Originally posted by daver2 View Post
                  Hi,

                  Thanks for responding.

                  I partially received your PM. The email I received as a result of your post contained the initial partial contents of your message. But, when I tried to inspect your message from within VCFED it was blank. For the mods. this may help them try and identify why some messages are appearing blank and others not? It is interesting that I received part of the message in my email though.

                  I don't post things to VCFED because of the size limit. In addition, VCFED is not really a platform for disseminating this type of information.

                  What I do is to scan a document, store it on my Google drive (other platforms are available) and send the Documentation Wizard (Al Kossow) an email with a link. Al will then "hoover it up" and put it onto Bitsavers for posterity and the benefit of the the vintage computer community.

                  Thanks in advance for sharing.

                  Are you "into" Cromemco computers by any chance? It is interesting to find quite a few people within the UK with a knowledge of Cromemco machines.

                  Dave
                  Seems to be some rocky bits with this board. No matter, I'll try other routes. I don't have any Dropbox stuff and eschew all things Google but leave it with me. I'll make sure Al gets a link so he can add it to the archives.

                  I have had a deep and abiding fondness for all things Cromemco since I think about 1978 not long after I built my first Imsai 8080 chassis. I wasn't interested in the Imsai cards, I wanted to see what the front panel did driven by a ZPU, some 16KZ's and a 4FDC. I have a bunch of cards still and a nice chassis (IMS 5000 I think) with a nice backplane (nicely terminated, active unlike the Blitz Bus but I still have one of those.) The current project is stalled as I haven' been able to get a 64FDC and a 1024KZ to go with DPU and the pair of TM848's to run up Cromix. I can just about get it online with a 256KZ and two TM100's which is still gratifying.

                  I'll PM you a link which should get you the manual for MU Basic so long as this board doesn't eat the URL.

                  BTW referencing another thread I also have amongst a pile of Cromemco boards three 4FDC's, two with RDOS 1.3 and on which I seem to have modded to take RDOS 3.08. I must have a note about it somewhere.

                  Lastly, does anyone remember this?

                  ByteShopUK.jpg

                  James
                  Last edited by jima; November 19, 2021, 06:40 AM.

                  Comment


                    #10
                    I remember the Byte Shop in Birmingham though !

                    I got my first S-100 system from there. A repaired Blitz-Bus on a wooden board with a power supply and a N* disk controller. I bought a second hand CPU and RAM card and I was operational.

                    The manager of the Byte Shop had exchanged someone’s damaged Blitz-Bus that he subsequently repaired and sold to me.

                    Dave

                    Comment


                      #11
                      I remember it very fondly too - I actually opened the Byte Shop in Birmingham and ran it for some years so we must have met at some point. My successors would never have been able to repair a Blitz Bus even if they knew what one was. I must admit, memory about that is a little hazy though. Oddly enough, I still run a Blitz Bus on a board from time to time - just can't find my ZPU and 16FDC at the moment. They may be with a 64KZ in the IMS chassis under a couple of Tektronix 7704A scopes. Time for a rummage...

                      Your message reply has shown up but header only and no text so I don't know if you have managed to download the manual. It has been a long time since I have used a board as dysfunctional as this one appears to be. I am loath to take this conversation off line as others may benefit - let me see if I can get over the 10-post rookie limit and try again. If all else fails we'll find another path.

                      James

                      Comment


                        #12
                        Perhaps a kind Mod will take pity on me and approve me so we can have a sensible conversation. I reckon 43 years in this business qualifies me as Vintage enough

                        James

                        Comment


                          #13
                          It might be 44 years as I spent a year at the Byte Shop HQ in Gant's Hill while the Birmingham shop was being found and prepared.

                          Comment


                            #14
                            Actually, 45 years might be closer as by then I had built two Nascom I's, designed an EPROM burner for it and with a colleague designed an S-100 interface for the Nascom, I recall buying a 4Kb static ram card and was then able to port Tiny Basic to it, still on cassette tape of course.

                            Comment


                              #15
                              Of course, the cassette interface for the early Nascom's was quite unreliable as (IIRC) the timing loop was wrong. A few bytes patched corrected this and made it quite reliable hence the need for an EPROM burner to build a new Nasbug to avoid patching every power cycle. I didn't have an eraser (couldn't afford one) so I pinched a sun-lamp from a friend and stuck the EPROM to it with a hair-dryer on cold setting pointed at it to stop the EPROM from melting. Several hours later - voila - blank EPROM. Happy days!

                              Comment

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