Happy 44th anniversary to the IBM Personal Computer!
Posted by 80sCompaqPC@reddit | vintagecomputing | View on Reddit | 40 comments
44 years ago today on August 12th, 1981, the IBM Personal Computer model 5150 was announced. This was the beginning of the “PC” as we know it today!
LousyMeatStew@reddit
Definitely a historic milestone but I wouldn't say it's the beginning of the PC as we know it today. IBM still intended the PC to be a proprietary platform, they just hoped to keep it closed by enforcing copyright on the BIOS.
When I think of the PC as we know it today - that being the PC as an open platform - I'd say it began once IBM's lawsuit against Compaq was dismissed. Without Compaq reverse engineering the BIOS and the subsequent dismissal, we would never have had the flood of cheap clones that allowed PCs to become the dominant platform.
DeepDayze@reddit
Then IBM tried closing it again with bringing the MicroChannel PS/2's to market which ended up being a dud some years later.
LousyMeatStew@reddit
Sort of. The home PC market had become a side hustle for IBM by that point and part of IBM's goal with Micro Channel was to design a bus they could use on machines other than x86 PCs.
IBM may not have regained market share in the home but MCA was still hugely profitable for them. They sold truckloads of PS/2s to their large corporate customers.
A few years later, IBM decided to enter the UNIX market and used MCA for their RS/6000 series well into the 90s and this was hugely successful. RS/6000 lives on to this day as IBM Power Systems and is the only platform left standing that hasn't either gone defunct or switched to Intel.
DeepDayze@reddit
The RS/6000 line certainly still sells for those shops looking for a UNIX based platform like AIX.
80sCompaqPC@reddit (OP)
By “beginning” I mean it’s the first ever machine to use the same architecture that all modern PCs are derived from. But yes, Compaq played a HUGE part in making the PC truly open architecture by legally reverse engineering the BIOS! I’m a big Compaq fan if you can’t tell from my username :)
LousyMeatStew@reddit
There's no denying that IBM made it and even if Compaq copied it, IBM made something worth copying. My first PC was an IBM PS/2 Model 30-286, I'm an IBM fanboy through and through.
Maybe the way I'd say it is that while IBM made it a product, Compaq turned it into a platform and to me, that's the value that the PC has all these decades later.
80sCompaqPC@reddit (OP)
I agree! IBM designed a great machine and Compaq played a big part in helping it become a fully open and compatible architecture.
I really like both IBM and Compaq hardware and that’s the bulk of what my classic PC collection consists of. Nice that you had a PS/2 Model 30 286 as your first! That’s one of my favorite PS/2 machines! Love the 286 with the compact form factor and ISA.
VladiciliNotRussian@reddit
Id still argue some nuance here. IBM did intend the PC to be semi open, as in all the technical data was readily available to promote third party expansion cards and development for the system. This was both unusual for the time and especially for IBM themselves.
The IBM PC 5150 is what launched intel into their golden age and what defined the “PC” as an x86 arcitecture system. It was also IBM that strong armed intel into giving AMD the x86 licence to keep a second supplyer for the 5150 and what gave them the springboard to become what they are now.
The nuance with history is it is always evolving. There are definetly key points for sure but Id say that Compaq successfully cloning the PC legally and Pheonix then licencing out a compatible bios to anyone is an evolution in the PC standard.
However without the PC existing Compaq would have had nothing to clone from. All modern PCs running x86 are code compatible with the 5150. Its the oldest compatible there is so I will argue that it is in fact the beginning of the PC.
However how we know it today kind of loses some meaning when translated over 40 years. Any DOS era machine is pretty alien from a user standpoint from their modern decendants. The openess of the standard also evolved over time, with or without IBM’s desire for it.
LousyMeatStew@reddit
Yes, but that's because that was how the home computer market operated. Apple II, for example, allowed third party expansion cards but locked out clones by enforcing the copyright on their BIOS. IBM was just following their lead.
To borrow from my reply to /u/80sCompaqPC, the way I see it is that the 5150 is a product while Compaq's actions turned it into a platform.
I'm not denying that IBM made something great, but it was also expensive and IBM was slow to keep pace with competitors. When IBM released the PCjr, it was a total disaster. Thanks to Compaq, there was a healthy market full of PC clones to lap up those sales and keep the platform thriving.
But if IBM were the sole PC manufacturer, would it have been able to recover and compete against the likes of the Atari ST, Amiga and Macintosh?
Psy1@reddit
The beginning of the PC as we know it would be more the 5170 as that is when clone makers decided to add their own standards onto IBM's as they didn't want to pay IBM for PS/2 tech.
80sCompaqPC@reddit (OP)
The 5150 was the absolute beginning of the “PC” architecture that we know and still use today. The 5170 expanded upon it with many new features. The PS/2 came out almost three years after the 5170 so I’m not entirely sure what you mean there. Companies like Compaq were making their own innovations with the PC architecture long before the microchannel PS/2 era.
Psy1@reddit
Prior to the PS/2 Compaq was not trying to be different from IBM. Even its 386 was a guess what a IBM 386 would be. With the PS/2 you had the clone makers for the first time come together for EISA and while EISA didn't do much it was the beginning of the IBM clone makers making their own standards without IBM and calling it a IBM Clone standard.
LousyMeatStew@reddit
EISA wouldn't be a good representation of what you're describing, though, because EISA followed IBM's 16-bit ISA design so closely that it was to its own detriment.
A truly independent standard wouldn't come until the early 90s with PCI although somewhat hilariously, it still followed IBM's mechanical design for the slots and card edge connectors.
Psy1@reddit
It was the clone makers making an IBM standard with IBM being allowed to give any input.
LousyMeatStew@reddit
IBM wasn't allowed any input into the Deskpro 386, either - but as you pointed out, it was "a guess at what an IBM 386 would be".
EISA was similarly a guess at what IBM would have done if they made ISA 32-bits wide. IBM didn't have direct input but EISA copied IBM's design choices for MCA - MCA had interrupt sharing, so EISA had interrupt sharing. MCA had software configurable allocation of hardware resources, so EISA had software configurable allocation of hardware resources.
Psy1@reddit
I think it was more at that time the consortium couldn't venture too far from the 5170 for their first project but it will. Also I'm pretty sure everyone in the consortium though that this was a permanent thing as IBM would keep making its MCA then come up with a different bus and so on.
Yet the consortium managed to sell ESIA as an IBM standard in a round about way by lumping it in as part of their IBM compatibility.
LousyMeatStew@reddit
The thing is, EISA is part of an IBM standard because it's backwards compatible with ISA. A computer with EISA slots is 100% IBM PC Compatible for this reason, not because of any additional "selling" that the Gang of Nine had to do.
This is why PCI seems to better encapsulate what you're talking about - that was a bus that was 100% new from the ground up and became a standard part of the PC platform purely through vendor consensus.
Psy1@reddit
An ESIA card is not, it would not work on a 5170 or PS/2 as its extra connectors were designed by the Gage Nine. What ESIA did was allow you to plug IBM standard ISA 8 and 16 bit cards into a ESIA slot.
LousyMeatStew@reddit
Right, but the notion of "IBM PC compatible" would refer to the system - the thing with the slots, not the cards themselves. Even ignoring EISA, not all 16-bit ISA cards would function in 8-bit slots and not all 8-bit cards were physically compatible with 16-bit slots. And for that matter, computers like the PCjr and 1000HX/EX had non-standard slots but still used the ISA bus.
So this was already a known commodity while EISA didn't make things worse, they didn't make things better either.
Psy1@reddit
IBM would abandon MCA for EISA prior to PCI so I would say EISA won that bus war.
LousyMeatStew@reddit
First off, that's not true. The latest system I can find IBM making with EISA slots was the PC Server 330, released in 1996: * http://ps-2.kev009.com/eprmhtml/epr3a/f8321.htm
While the latest system I can find IBM making with MCA slots were part of the RS/6000 series in 1997: * https://www.ardent-tool.com/RS6000/ENUS197-064.html
Second, that's not really the point. EISA was a bus whose design was both heavily influenced and heavily constrained by decisions that IBM made. They were still copying IBM (both in backwards compatibility with ISA-16, and copying features from MCA).
Psy1@reddit
You just listed IBM using EISA and your MCA example was long after the PS/2 was discontinued on a non X86 system.
Copying IBM would be ESIA looking like MCA but instead ESIA copied HP with its dual connector design.
LousyMeatStew@reddit
Busses aren't tied to processor architecture. EISA was used in non-x86 systems as well.
Your statement was that IBM abandoned MCA but they clearly didn't. They used MCA as the primary bus of a higher-tier product line while EISA was the secondary bus on a lower-tier product line.
Context is important: I said "copying" in the context of copying features from IBM (which they did) and being restricted by IBM's prior design (which they were). Just because they didn't copy everything is not the issue.
Psy1@reddit
Yes but the advantage of EISA is lost when you remove its legacy support. At that point you just have an ISA slot with stacked connectors to get to 32-bit.
But they didn't, EISA lacks the features of MCA as they didn't go down the route of legally distinct bus where changes are made just to not infringe on patents. EISA also didn't just extend the line of connectors like IBM did going from 8 to 16 bit ISA but copied HP's slot design to have two levels of connectors.
LousyMeatStew@reddit
Sure and that's precisely the point - the Gang of Nine didn't create a 32-bit bus. They grafted 16 additional bits onto IBM's bus. You can't say that IBM had no input when half of the bandwidth is provided by IBM's original design.
It's like publishing a sci-fi novel but the first half is a word-for-word copy of A True Story. It's in the public domain so it's legal to do so, just like it was legal to copy ISA. But what you have is a derivative work, not an original one. It could be great. You could have an amazing second half that really builds on the existing work but it's still derivative.
History has also shown that this decision was wrong. PCI came along only 4 years later and would eventually become ubiquitous despite completely foregoing backwards compatibility. And to be fair, they also showed that IBM was wrong in trying to keep MCA proprietary, but I think that's a given.
Psy1@reddit
The engineering is more complex then that or we would have 128 bit PCI slots now. Also EISA did include bus mastering support but by then Amiga and Mac had that too by then along with the vast majority of Unix workstations.
It was the right decision, as I said Amiga and Mac already had moved onto modern busses. EISA was the way it was because the consortium didn't have time to make a more complex solution.
LousyMeatStew@reddit
The complexity is due to backwards compatibility. EISA had to be backwards compatible with ISA bus mastering so they needed to add 32 dedicated address lines. They also didn't fix any of the underlying limitations - limited to 6 bus masters and 8mhz bus speed, both due to ISA backwards compatibility.
IBM fixed how bus mastering worked. Bus arbitration circuitry was included in the DMA controller and you could have up to 16 bus mastering slots, plus you had more bandwidth since MCA could run up to 20mhz.
As far as comparisons to other busses, EISA is completely outclassed by NuBus90 and Zorro III was it's own beast. MCA at 32bit/20mhz, on the other hand, could keep pace with NuBus90 but it doesn't really matter. Macs eventually switched to PCI regardless (again, eschewing backwards compatibility) and we never saw a true Video Toaster on the PC.
80sCompaqPC@reddit (OP)
I would argue that unlike most generic clone makers, Compaq computers were always more than just a direct copy of an IBM. Compaq always added something extra. Like the dual-mode graphics of the portable and the use of an 8086 instead of an 8088 in the Deskpro. Compaq was always making innovations. But yes you are absolutely correct that EISA was a response to the proprietary microchannel architecture that IBM created.
Oh and Compaq’s 5170 clone, the Deskpro 286, ran at 8MHz instead of 6MHz AND came in a Portable version with the Portable 286. I would really say that’s “not trying to be different from IBM” myself.
Psy1@reddit
Compaq was not alone. Commodore did a lot of work consolidating logic into ICs and did throw in a port for its 1352 mouse that on board runs off the same logic as the Microsoft Busmouse.
80sCompaqPC@reddit (OP)
I wasn’t aware Commodore did that with the mouse interface, very neat!
Psy1@reddit
Yhea they did that so their 1352 mouse (Amiga) would work with MS Busmouse drivers on their IBM compat line.
NefariousnessOne2728@reddit
I remember when they brought them into our office. It was great.
Kiwi_eng@reddit
I cherish the two in my small collection that look nearly brand new and still have the original caps throughout. I even lucked out with DOS 1.0 and its binder. My first computer at work was a 5160 but was only used to play "Leather Goddesses of Phobos" during lunch. I did my actual work on paper, lol!
LittlePooky@reddit
I love those manuals that came in a slip case. Got a few - first one (for Compaq Portable) was MS-DOS 2 (it came with PC-DOS 1.1), then WordStar, and later, after I added a hard drive on a card, was Xerox Ventura Publisher (that was expensive, but I didn't pay for it).
80sCompaqPC@reddit (OP)
Yeah, I love those manuals, they are made to last! They sure don’t make stuff like that anymore.
LittlePooky@reddit
I still use (Corel now) Ventura Publisher. It has a lot of controls over the output (during printing). I bought some half-sized binder (like this https://www.amazon.com/Avery-Durable-Binder-2-Inch-27554/dp/B0006HV8V2) and tell the program to print "booklet" and it formats it correctly (HP laserjet / inkjet drivers can do this too by the way). Using a paper cutter, and a hole puncher, I can make more or less home-made book. Haha!
Noodler75@reddit
When we got one at my job the first thing we ran on it was: Flight Simulator.
droid_mike@reddit
That game was revolutionary at the time. If you try and run it now (I have), it feels like absolute garbage. According to flight Simulator 1.9, there is only one building in Chicago... The Formerly baked Sears Tower. Nothing else. And it runs at a whopping 2-4 frames per second. If you don't believe me, it says it right there in the manual.
Foreign-King7613@reddit
Already? Feels like yesterday.
DeepDayze@reddit
The beginning of an era!