IBM 5100 Discussion Clarifications

Notes and clarifications/corrections to the IBM 5100 discussion that was presented in June 2023.


PowerPoint and PDF extended version of the presentation:

Documents related to CORE and PC-51:

01:45 I didn’t want to talk too much about the SCAMP as it wasn’t the focus of the presentation,
but to celebrate its 50th anniversary I did want to be sure to at least cover a bit about it.
And when I said the SCAMP didn’t have a power supply, I meant it didn’t have an integrated/internal power supply, and I was emphasizing how the SCAMP wasn’t yet a portable system, but the overall industrial design was along those lines. Also a subtle note that early 1970s, along with the great microprocessors advancements, there were also great advances in compacting power supply design.

02:32 I forgot to request for the presentation to also capture my mouse movements, so some of the discussion ends up confusing since I’m sometimes speaking to an aspect towards where I am pointing with the mouse. In this case, I was pointing to the picture of the blue IBM 1130. And yes, I did mis-speak about typewriter/teletype, and just meant keyboard. I paused here realizing that mistake, but had to press on since I knew there would be time constraints.

03:04 I have had people comment/ask about how a 1970s systems is related to the PALM pilot, which is not actually the case here. There were some stories I wanted to share about that, but I decided I had to skip those due to time constraints. That’s why I had to quickly wrap up any more discussion about the PALM Pilot before I got off into the weeds about it.

03:41 As can see in the “extended edition” of the slide notes, we’ve also found a 1976 document that mentions PALM. But I didn’t want to distract from the flow of the discussion on GENASM.
If anyone is aware of an even earlier reference to PALM, would like to hear about it.

04:13 HJ Myers also has his signature on the last page of the printed document, so it maybe was his hardcopy of this document, which is why I think the “6 PALM” stuff is his handwriting also.

04:37 It’s a subtle point, since when we hear “x86 instruction set” we think of the assembler code
associated with that, not the actual Intel microcode and specific hardware implementation.

04:44 Again, saying “these two chips” was referring to where I was pointing with the mouse, which was the two white vertical chips on the processor card. In later variants of the PALM Processor card, those white chips are sometimes the more modern black encasing.

12:32 Misspoke, didn’t mean “300 byte”. The tape storage capacity is actually 207KB for the DC300’s and newer DC6150 cartridges can store about twice that.

12:53 QIC = Quater Inch Cartridge (I misspoke and said Quater Inch Tape). In my haste and in my head, tape vs cartridge meant the same thing.

13:30 IBM had developed the 8″ floppy format around 1970, having it available on both the IBM System/370 and System/3 by about 1971. The 8″ floppy wasn’t support by the initial IBM 5100 in 1975 (which IBM was just pressed to just get the product out the door in that year), but it was a major addition to the IBM 5110 in 1978.

15:28 or aka PC-DOS 2.0

16:11 “driver” meaning microcode (PALM) being loaded into RWS

16:52 CORE related documents are now archived here

16:56 I meant CHM (as opposed to VCF), but CHM would be more interested in original hardcopy documents

17:09 BASIC is a decent introductory language, but the line numbering does limit the scalability that later more structured languages offer (such as even QuickBASIC)

18:03 In my haste, several times in my mind I was referring “IBM PC” as the IBM 5100 Portable Computer, not the later IBM PC 5150. But I was inconsistent about this, apologies for that.

18:18 The 3000 number may have applied to the CoreNet hard drive equipment (it was in another CoreNet newsletter) which in any case was still in the same ballpark price as the PC-51 software itself

18:30 As before, PC-51 user manual is here

19:18 POS (position) index might be 1 based instead of 0 base

19:21 “how long” referring to the length limit of the input field (in this case, set to 18 characters)

19:37 meant “business organizations” (not business computing)

19:51 Further note: in the IBM manuals, they refer to this concept of formatting as “Images”
that was confusing to me since I thought “Image” was referring to the more modern
concept of high resolution graphics – but no, “Image” on this system was just referring
to the format convention of how numeric data is presented.

19:55 the international character set is defaulted by the jumpers on the display card,
but then there is a keyboard shortcut code that can be issued to dynamically swap between
international symbol sets during runtime usage of the system. These sets aren’t available on the 5100, only the later systems.

19:57 The FLS (system file) is not a literal file on tape or disk, but rather mapped to a region of memory. The settings are not remembered across restarts of the system.

20:43 meant “Sharp PC-5000”

26:02 meant “public” or “included with the system” IBM documentation (as opposed to “internal confidential” IBM documents).

26:48 meant “IBM 5100 display card” (forgot the words “5100”)

27:01 meant “increased the capacity of the solid state boards” (more than doubled the density)


29:25 Alvin Ginseng letter on is some of the justification to what I am saying here
re. IBM internal “non-concurrence” disputes across departments, and the legal compromise on justifying the incorporation of BASIC

31:18 maybe pull-down resistors

32:02 to clarify, during that first cycle of startup, Register mode is not actually showing
register values – but you can still use Register mode to read the ROS values in hex. After the next cycle of execution, this changes from there-on afterwards to actually do display Register values.

32:10 OCR object character recognition, using a static image from a camera and then OCR
that image to convert the displayed values into a binary file that contains the PALM machine code sequences.

35:27 Didn’t mean “older” but clarified that PALM is different conventions than the more traditional IBM mainframe code.

36:18 “he” being the authors of VisiCalc (Dan Bricklin / Bob Frankston)

39:42 Changing the presentation was going to interrupt the recording process, so that’s why I couldn’t show the FF code more clearly. It is noted in the presentation documents, you’ll have to scroll over or zoom out on the page.

42:17 to emphasize: first evidence of AUDIO tapes. Certainly 9-track tapes or similar had been in use for over a decade.

42:40 meant “raster graphics” not “vector graphics”

43:43 I forgot to mention, the System/3 didn’t have traditional registers as we were
familiar with them. everything had to go through main memory. The IBM 5100 is a
hybrid of this, where the first 128 bytes is more directly addressed-mapped
to onboard components refered to as registers.

44:51 this looked off at the angle to the screen that I had at the time, but is actually all correct

45:20 “all this” was referring to the lower center part of the table (forgot to request the recording to include mouse movements, that would have helped clarify a few aspects here)

45:45 “same” was referring to the same colored ones at the lower part of the table, not the top part (and they “dark olive” colored ones did point to an address, all the same address, but the jump location basically indicated a system error and halted – i.e. “invalid opcode”)

46:16 meant “punch card readers”

46:24 perhaps multiple punch cards in use to speed up compilation?

47:25 meant “C2” not “72”

48:30 for a demo of some of the things that native PALM machine code can do, see my video presentation here.

49:35 originally wanted to talk more on PALM and go line by line in the example and the instruction impact to the registers, but just out of time for this session. Will prepare a follow up eventually on the PALM instruction notes that I’ve prepared and consult during my own development.

49:50 the left side portion is what is “discovered” since I never found those aspects mentioned in the IBM MIM documents. But the DCP itself is very well documented in the MIM.

50:12 this early-press key code feature isn’t always working in the emulator

52:25 clarify, “logic manuals” not the same as wiring diagrams

53:11 meant 5100 works differently

55:03 Wanted to say, I have a lot of respect for Wang Computers and what they accomplished in 1973 (and Dr. Wang’s contribution of Core Memory to IBM a couple decades prior to that).

57:46 meant +12/-12V also (accidentally repeated 5V)

01:01:00 For those who didn’t watch the end, there is a brief discussion on John Titor and subsequent Steins;Gate anime relationship (both of which are related to the IBM 5100). I hadn’t prepped to talk a whole lot about it (and was running over the time limit), but there are some existing YouTube presentations do cover that fairly recently. As a couple examples:
The Why Files HERE (2022)
RetroRecipes HERE (2021)
Epic Summary of Stiens;Gate HERE (2018)

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