Remembering the IBM PC It's time again to rewind that fleshy cassette storage device in your head to yesteryear. This old box logo This week, we're headed back to August 12, 1981 — the date IBM introduced its Personal Computer, a system that would shape the industry and make the term "PC" synonymous with home computers. But let's not get ahead …
Motorola was quite determined to get the business for the IBM PC, but the 68000 at the time was a huge chunk of ceramic - a 64-pin beast that swallowed too much real estate. It was also in a gold-pinned package, which made the socket expensive as well (manufacturers didn't use dissimilar metals for packages and sockets). The 8088 eventually chosen for the PC was in a 40-pin package with tinned leads, and used an 8-bit bus. Motorola's 68008 was about four months too late.
MC68008 - ah, the Sinclair QL. Loved it. Developed for it and thought it much more of a step forward from Z80 than, say, the Spectrum was over the ZX81. But since when has "technically better" sold kit? Especially when hugely expensive like the PC ranges were before about 1995. After all, IBM's PS/2 MCA was a better standard than ISA, (even though it could be seen as IBM trying to drag things back into its playground), but no-one wanted to spend money on it.
I've still got an unbuilt kit version of the ZX81, so WRT the 'grandfather' thing being wrong, I'd say the ZX80 and ZX81 were the last of the line before the beginning of the pre-built systems like Spectrum, BBC Micro and, yes, IBM PC - just because it can be built from bit doesn't mean it's anything like an Altair! So for me, the ZX81 would be the last grandfather, very much in the spirit of the earlier late-70's kit. Later stuff was limited to plugging in CMOS chips to upgrade RAM, or adding functionality through extra ROMs, or just buying pre-built expansion systems.
Prestel: IIRC there was an edition of the "Making the Most of the Micro" TV show where two Beebs exchanged an message across the Atlantic to show the ability to swap data over telecoms networks (would be about '85 or '86, so just after the Internet switched to TCP/IP, but before WWW). The data exchanged okay, but the program fell over because the BBC Micro had region-specific spellings in the version of BASIC they used (couldn't have an educational micro with 'spelling mistakes'!) - the US programmer in the New York studio had used the word 'COLOR' where the UK micro was expecting 'COLOUR' and the program crashed - when corrected, it drew a big red apple.
Must book my trip to Bletchley Park - the National Museum of Computing (http://www.tnmoc.org.uk/) looks stacked full of geeky goodness. Are the photos for this series of articles taken there?
IBM may have documented "everything" in the PC's Tech Ref manual, but amazingly "everything" didn't extend to the PC's expansion bus (later to be known as ISA). Most people had their own definitions based on analysis of the states, timing and levels generated by the 74-series TTL chips on IBM's PC schematics. IBM didn't release a bus definition until the RT Tech Ref (it looked like the RT team had gone through the same analysis process themselves), and by then it was academic.
A generation of clone-designing hardware engineers lived and died by whether their designs' busses were "close enough" to what that pile of TTL did - which could get tricky when it was stretched to cope with later CPU generations like the 386.
In a sense, I'd disagree with the ZX81 being the last of those in the spirit of the 70's. While the kit did involve soldering everything together, if I remember rightly the ZX81 consisted of the CPU, RAM, ROM and a custom gate array - just 4 chips.
To my mind it was the introduction of the custom chips that brought about the demise of the 70's spirit. Probably the last of the line in that scheme of things were systems like the Acorn Atom and Tangerine. Provided you had the schematics (and back in those days, you did get them), and had access to the ROM images, it was quite possible to buy all the components from somewhere like RS or Farnell and build your own version without needing anything special from the manufacturers. With the old guard using standard components and a pile of databooks, you knew exactly what was happening inside, and it made it so much easier to mess with the hardware.
Umm, I have only seen one person dare to claim they wrote in assembler.
I am past caring about my age, but when the boss bought the IBM PC-1 with 256K of RAM via an IBM friend, I thought "how amazingly small these new things are..." :-)
I trace my computing back to 1969-1972, the era of 80-column punched cards, 15-inch and 17-inch fanfold stationery, 24-hour turnaround at the job collection window, 5th floor of the Institute of Technology where I trained in Accounting. There was the one register per instruction ICL George 3 OS running nearly 1000 jobs per day in 96K of core memory. This was the era of showing employees a room full of whirring machinery and saying "there you are, that's what calculates your pay." "Wow!" (Witnessed that conversation over and over again.)
I bear the scars, but I am sure there must be others who pre-date me...somewhere! Fellas? Anybody still here??
The second argument to a POKE would never be 256 -- POKE stores a single byte value (i.e., 0 to 255) in the address given by the first argument. Could have been 255, maybe.
The number 234 crops up often in POKEs for Commodores, Apples and Beebs (although the Beeb didn't actually use the word POKE, but a construct using ? as an operator, such as ?A=B; there was also an analogous form using ! to poke four bytes at once) as it is a NOP instruction on the 6502. The Z-80 used 0 for NOP.
Er ..... I'll get my coat.
> No no - they were but the first pre-built & badged generation to be sold generally.
> Some of us were wielding soldering irons and working on binary dumps for a few years before things got wrapped in fancy plastic - er, or any case at all...
You are correct, that was before my time.
I bow to your experience ancient one!
Fair enough - the 4-chip thing is why some courses still refer to the ZX81 as being a classic in computer design, with the major functions identified in separate chips. Still, I had a ZX80 for a while - 24 chips in that one. IIRC the reduction in numbers was down to the custom logic design - not much could be done with CPU, RAM and ROM, so how about the ZX80 as last 'in-spirit' design? There must have been some overlap where the techies became mainstream - they can't have all gone through Acorn!
On a slightly different tack, and bringing it back to the IBM PC, if we look at more general chips in a PC, how about the RM 186? This was of the era when companies tried to produce IBM-compatible PCs, rather than clones. Not much fresh air in those boxes, and the check of compatibilty always seemed to be whether Flight SImulator ran on it.
> BTW Atari Amiga? hand in your geek badge at the door man
<sorrow> it's true, the grey cells are wearing thin these days.
I remember trying to write a program in assembler on my TRS80 Model I Level II but gave it up as a bad job (which it was) and waited for something better to come along...
I think you will find that the memory immediately above 640k was originally taken by the CGA memory map.
I still remember the pain and misery of trying to get DOS memory optimised so that our programs would work.
Who else remembers that there were 2 different types of additional memory - extended and expanded?
The authors of BASIC have written a book called "Back to Basic" that may amuse readers.
As far as choosing the 8088, I also heard that the large body of 8085 code played a role in that translators were used to convert 8085 assembler into 8088 assembler (and rather poorly at that -- check out the original PC bios one day #6-). Being a great fan of memory-mapped peripherals and not a great fan of segments, I have often rued that day.
IBM, recognising their total lack of experience in this sort of development, did indeed OEM as much as they could. The 8088, regardless of all other merits, had a complete chipset ready to support it.
Because they had OEMed everything, the only part of the PC which could be protected as IBM’s intellectual property was the BIOS. The engineers assured management that nobody would be able to produce a 100% compatible clone without using the IBM BIOS. Anyone who did would either licence the BIOS and compete with IBM on very unequal terms, or steal the BIOS and be sued. Either way, IBM wasn’t worried.
However, it was possible to “cleanroom” or “blind reverse engineer” the BIOS, replicating all the functions it performed, but without copying it or even looking at it. A few companies did, and sold their clone BIOSes to everyone. Then a chip design startup called Chips & Technologies, while waiting for the chip design work to come in, took it upon themselves to reengineer the Intel chipset, reducing the part count from 63 chips to 12. They licensed this design to everyone.
As a result of this, anyone could start manufacturing PC clones and match IBM on price. And so the PC began to pull away from the IBM brand and move towards becoming a commodity item.
I remember the dreaded tape on its predecessor (& on acorn's + bbc micro) but not the 5150 PC1 or is it that my brain is succumbing to the early onset of the dreaded A disease?
A very simple machine and let's not forget (it was probably in an earlier post) that the reason why it took off was because it was Big Blue. The likes of Apple, Atari etc were not to be trusted with big corp's data and services. I can remember working for an American defence manufacturer who forbade until relatively recently (15 years ago) that the PC & their applications were not to be used for critical applications (invoicing, accounts you know the stuff that helps make the world go round - stuff the computers).
So forget all this twaddle about the technology. Gates & co also recognised that companies were not about to reinvest in new applications - hence the failure of OS/2 - multiple DOS boxes could have been put in there - betamax lost to VHS on marketing & how much better *it* was and twas ever thus...
"Umm, I have only seen one person dare to claim they wrote in assembler."
Well, 6502 was a hell of a lot more fun than any of the 88* 86* but back in them old days sometimes you just had to get out the hex editor and mung the sucker for a while.
I still have my copy of _The Programmer's PC Sourcebook_ with a listing of Register calls (but I just had to look for it, it has been a while).
DOS prompt, command prompt; has anyone looked into the evolution of this since passing the torch from the 98-ME platform to the NT?
I have.
"My God, it's full of asterisks."
I joined the industry about the same time as you and, over the years have written more assembler and COBOL than I care to remember, though in the last decade my C output has just about caught it up. In summary:
My first computer was an Elliott 503 that I learnt Algol 60 on before graduating.
In 1968 I joined ICL and spent my next two years writing PLAN 3 assembler before learning COBOL. Then it was George 1, mini-MOP, George 3 and programming in COBOL, JEAN, PLAN, the PLAN macro-generator and Algol68R.
Since then its been ICL 2903, ICL 2900 and no more professional assembler. Then on to Stratus, Tandem NonStop, DEC VAX, S/38, S/88, AS/400 in COBOL, TAL, PL/1, RPGIII, C running under VME/B, VOS, Guardian, VMS, OS/400, Unix.
Home stuff:
MC 6809, Flex 09, lots of assembler, PL/9, BASIC and C
MC 68020, OS-9, C, Sculptor 4GL, some assembler
Intel X86 - no more assembler, but lots of C and then Linux, C and Java
======
Re: the IBM 5150 and speed
The IBM office automation systems of the era (System/3, System/34 and System/36) were notoriously slow. They did all arithmetic using variable length packed BCD values. I remember hearing rumours at the time that IBM had mandated that the PC must not be faster than an entry level S/36 in case it affected S/36 sales.
Shortly after the 8 MHz PC-AT was launched a third party S/36 emulator, the Baby/36, appeared. It emulated a S/36 with one terminal and would run all the standard S/36 software including the development tools. IBM sales guys hated Baby/36 because, on a PC-AT, it was quite a bit faster than an entry level S/36 and a fraction of the price, but S/36 developers loved it.
Contemporary non-IBM clones were generally faster than IBM PCs. IBM salesmen, dyed in the wool mainframers to a man, really put the PC down as a piece of insignificant garbage. So, do I believe that IBM PCs were slow by design? Definitely!
Never had audio cassettes as storage... The Adams, Atari's, Trash 80's and Commodores used an audio cassette as a storage... Apple ///'s which with the proper hardware, could be backed up to a standard VHS vcr... No, I'm not making that up. But in all my years I've never seen an audio cassette storage device for an IBM PC.
I remember when the world actually blinked in awe at a 10 Mb hard drive... And the only way to address memory over 640 K was to use the LIM spec sys files...
Anybody remember what the LIM stands for in LIM spec?
The reason why IBM didn't write the OS for their PC may be the same reason that ICL had problems getting its head around small computers -- they literally couldn't think down to that level. You really have to hear a heavy duty mainframe OS type try to describe the inner workings of CP/M and then map that to a quick and dirty disassembly of the CP/M code. They also were convinced that nothing useful would come of these small systems - yes, they were limited but somehow they didn't get the idea that stuff tends to get more powerful year by year.
MS-DOS's earlyest incarnations was a direct rip of CP/M, right down to the system interface. For v2.0 they added a bunch of Unix type system calls (leaving the old CP/M style in place). Its one of the ironies for those who have to listen to Microsoft going on about 'ix' people 'stealing their ideas'.....I suppose if they keep it up long enough all the people with the long memories will die off and then they will have truly invented computing.
BTW(1) -- BASIC -- Beginners All-purpose Symbolic Instruction Code
BTW(2) -- You can back data to and from a cassette drive using just a handful of gates and bistables. You don't even need a processor. Its was a bit slow but it worked. My very earliest systems just dumped memory to/from tape -- kind of useful if you were just trying to get a processor to work.
LIM = Lotus Intel Microsoft
Wasn't the 8086 segmented memory/640K limit due to backward compability with the 8080 64K address space. IIRC it was so that you could have 10x programs running at the same time in their own address space?
Had a spectrum with 48K at home, always fascinated by the IBM POST, watching it count all that memory....
I used to sell them. The original IBM PC had only five expansion slots. The explanation of rocker switches in the manual of the expansion cards were the pits!
I also had an IBM PC Portable. Modified it by taking one of those slim line floppy drives out and replacing it with a 20Mb SCSI drive. It had to be a SCSI drive because there was only one free slot and it was next to the CRT. The 8-bit SCSI card was short enough to fit in there.
"Wasn't very hard as mom Gates was a member of the board in IBM at the time and IBM expected to sell a couple of thousands these small toys, insignificant. Also made very simple to "choose" junior Gates as provider."
Not that I love Billy-boy, but Gate's mom was NOT a member of the IBM board - his father was a hugely successful Seattle lawyer, and mom did the charity-work circuit. She was on the board of the Seattle Red Cross (if memory serves), WITH the wife of an IBM board member. There WERE no female execs of that level in the US at that time, as a general rule. And her position didn't determine that Bill got it, but she DID get him the introduction.
Prior to that, Bill had already made a major name for himself crafting languages in the orginal homebrew PC world, and had legitimate credibility from his work on SWTP's or IMSAI's BASIC if I remember. He was also (before he bought & sold PC-DOS) a founding member of the "software should NOT be free" brigade, taking out ads and publishing papers on the need to protect intellectual property and prevent the mass-copying of computer software.
In short, Bill Gates was an active member of the PC industry BEFORE his mom ever made any introduction for him. But as someone who used to be a professional CP/M programmer myself, I wish Kildall had been in the office...
Robert
@bws: IIRC the IBM PCjr could be specced with tape drive - all storage was seen as optional on that, except for the twin ROM slots below the external drive bays. Granted, most shipped with a 5.25" floppy drive instead, but I have vague memories of the adverts for that PC variant showing a tape drive setup.
Granted, it's not a proper IBM PC (lots of incompatibilities), but was IBM's attempt at making the full-blown business PC more home-friendly. Actually, the PCjr was quite innovative - wireless keyboard from the start (IR, not radio), the cartridge-based storage idea and a few other things like wireless joysticks that didn't make it out of the factory before the whole idea was pulled. Apart from these things, which we're seeing today in a different form (Bluetooth connectivity instead of IR), the only other thing of note was that everyone wooed the home users for far less cash - apart from Apple. Plus ça change?
And WRT using video tape as a backing store, this has made appearances over the years in several guises. After going through a variety of interface systems it eventually faded away, presumably due to cheap HDD costs, plus the fairly slow speed (ArVid was in the 300kB/s range, though Danmere Backer reckoned to be about 20-30 times quicker). However, there are still plenty of USB VCR capture devices, for pulling video from VCR.
If you're going to speculate, here's one to run with.
What if RMS and a few friends had gatecrashed the next meeting of the Homebrew Computer Club after 03/02/1976 (the date of *that* letter), dragged Bill Gates into the Gents', administered a Damn Good Kicking (TM) with optional head-flushing -- and then worked on a new OpenBASIC interpreter, which would be faster and better than Microsoft's?
Hey, a guy can dream .....
IBM was trying to market to schools, with the hard drive before they released it to the general public. In the spring of 1981, when I was in eighth grade, the "exceptional students" were allowed to go to a local vocational school and "play" with these "cutting edge" microcomputers. I was in Heaven when I arrived as I had been previously programming on a TRS-80 Model I.
They had a sweet setup. The 10+ computers were networked to the hard drive and had the two 5 1/4" floppy slots.
The principal of the vocational school gave some speech with the IBM suit and blathered on about the need to be careful and how gracious IBM was to allow our school to be on their tour. My attention lasted about 10 seconds. In 15 minutes I was hacking away writing some simple BASIC. I started messing with the DOS and lo and behold, I was able to access the hard drive. After another 15 minutes or so of tinkering, I made a BIG mistake. I asked the suit about the hard drive and showed him my screen. I wanted to know what some of the files did. He blanched, whispered to the principal, and my computer time ended abruptly.
Ah! Those were the days. Sadly, even though I've spent nearly 29 years working with computers, I've never learned how to program efficiently. I then made the bad decision to get art and English teaching degrees in college. Finally, I'm returning to my roots and working on my BS in Computer Science.
I should have realized my IBM experience at that moment in 1981 was an epiphany, because working in the architectural field (buildings--not software) sucks.
SIDE NOTE: I've been reading the REG since it started, but this is the first time I've ever posted anything. Great site, and I roll with laughter when the Brits bash us Americans--sometimes the truth hurts (ha-ha). FWIW, I'm one of the gun-toting ones and am federally licensed to sell machineguns, silencer's and various other goodies to law enforcement and certain civilians.
Yes Mr Sugar (later to be Sir Sugar) did introduce the 1512 and 1640 models in the early 80's, but like a lot of other AMS devices they weren't very well thought out and failed in the market.
In NZ my dad bought us a 1512, which sported twin 5-1/2" floppy drives (hard drives weren't yet readily available for PCs) and a very fancy graphics chip, which if I remember correctly could reach the (at the time) almost unprecedented range of 512 colours. Quite a step forward from 16-colour CGA.
Still, no software we ever came across apart from Amstrads own demos could drive the custom chip, and shortly after Amstrads PCs dissapeared from the shelves never to be heard from again.
did they drift off into making hardcards ? (harddrive with a isa controller card).
Then bought Sinclair and died?
Nearly forgot the word processor things; sometime around then also.
BTW I nearly bought a MK14,then ZX80,nearly a ZX81 but bought a motorbike instead who knows what could of been. :)
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