I know that IBM invented the PC, but what was the first ever model to conform to current specifications of what we call a PC? Some people say it was the PS/2, some people say it was the PC/AT.
Does anyone know what kind of hard disk it had and how much RAM? What OS did/ could it run and what applications were available for it? If I had one in front of me now, would it theoretically be possible to “upgrade” it to run Windows 2000?
I always thought the TRS-80 was the first personal computer. do I have my dates wrong?
I’m sure you’re right, but I’m talking about the first computer that could run Microsoft DOS or anything like what we have today. I know that all PCs are based on an IBM computer that was cloned and improved upon. My question is, what computer was that?
The PC XT came before the AT, and the PS/2 came much later (late’80s). I don’t think the original IBM PC was designated XT though.
So back to my origional question then, which was the model for modern PCs?
From The IBM PC’s Page:
Thanks Beatle, I’ll go take a look 
Well, my initial thought was that the Altair 8800 was the first personal computer, but according to computerhistory.org, the Kenbak-1 came before it, and the Altair was first to coin the “personal computer” phrase. IIRC, IBM’s inventions was to call their product the PC (as opposed to “personal computer,” I suppose).
Now, someone please correct me if I’m wrong
Regarding the OP, I think we need to define what “current specifications” are. ISA slots vs. PCI slots? CPUs with virtual machine capability? If we’re talking about operating systems, then even Windows Me was written on top of DOS, which has been around at least since the 8088 IBM PC running from floppies.
Well, it’s like trying to install Windows on a Sun SparC box. Not possible, right? That’s because it’s a different platform. I guess I should have said "When was the modern “PC Platform” established and what was it’s name. The link the Beatle provided is very interesting in somewhat explaining such things.
And in case you didn’t know, that original IBM 5150 Personal Computer, with no hard drive and 64K (not M, but K) of memory cost - drumroll please - $4995.00
That’s right. Five grand!
Wow, kinda makes you think think that Microsoft aren’t asking too much for Windows XP after all. What a minute, OF COURSE THEY ARE!!! 
My first computer was a TI/99-4A that cost $250 in 1982. I bought an AT with 640K and a whopping 20 MB HDD for $6000 in 1986. IBM was able to keep their prices higher than anybody else for a long time {“Nobody ever got fired for buying IBM.”) and that was what eventually did 'em in the PC market.
And my first 1 MB SIMM cost $450 in '88 or '89.
Cool, but what did 'em was their war with software vendors (IMHO). Haven’t you ever seen the movie “Pirates Of Scilicon Vally”? I gues some would say that the first real OS was FORTRAN on the Altair.
Anyone wanna set me straight here?
Small desktop-sized computers of many brands were around before the IBM PC. Most required assembly by someone who could wield a soldering iron, for starters. I can’t recall that we ever called them “Personal Computers.” I think IBM might not have coined the term, but they were the first to apply it to a particular brand/model.
Altair and IMSAI were the first that I would call “personal” or desktop. They came out in the mid-70’s.
The IMSAI had an 8080 CPU at 2MHZ (that’s meg, not gig), zero RAM (obviously you had to run out and buy some after you soldered the motherboard, and a 1K mem board took up a whole slot), no external storage of any kind, disk or tape, no keyboard, no monitor/terminal, and no software; certainly no operating system! It was just a box with a power supply, a CPU board, an I/O (2 port 8-LED output display, 8-switch toggle input) and 22 expansion S-100 slots. It cost $500 (kit).
The first IBM PC had a 4.77Mhz CPU, no hard disk, 12" monochrome (color optional with 4 colors and greatly reduced resolution) memory-mapped display (320x200 dots, I think), 2 5" floppies (90K?), keyboard. I’m not sure how much RAM; it might have been 64KB. It had a boot ROM with BASIC, or you could boot into PCDOS 1.1 (a twin of MSDOS and a ripoff of CP/M), which had no “folders” or sub-directories possible. It was a big step forward, and I mean that sincerely!
I’m drawing this from memory (mine) and might be off just a tad on the specs, but not by much.
Could you upgrade it to run Windows XP? This takes two kinds of answers. First, Windows tests the hardware and refuses to install the Op Sys if it thinks it is not beefy enough, so it would definitely fail there. Second, if you could circumvent that, add enough storage, RAM, minimal peripherals, etc. just to contain the system, modify the system to recognize hierarchical directories, etc., etc., it would probably take, (these are WAG figures) 39.5 days to boot. Displaying a single icon would take 27.1 minutes. Loading WORD would take 92.8 more days – get the picture?
If you ever try this, it could be a lot of fun – ya got the time?
And Greenkeys, the PS/2 came after the AT.
Fortran is a language, not an operating system. I can’t recall if it was available for the Altair or IMSAI, but I did buy an 8K BASIC on cassette for that machine. Because it didn’t have an operating system, you had to patch some addresses to tell it where to send the output and where to get the input before anything would work at all, and you had to write your own drivers from scratch for all peripherals, including keyboard. Strictly hobbyist/hacker territory.
The first true (PC-type) operating system I ran across that was not designed for a particular brand of machine was CP/M. You still had to patch it to match your machine and hard disks were not affordable for most. I paid $1800 for a Micropolis dual-floppy unit (360K ea floppy, single-sided) and it came with a very crude operating system, BASIC, and an interface card. It would work with any S-100 box (Altair, IMSAI or homebrew) which was becoming a standard.
I still remember the ads – “Buy a S-100 unit! You’ll never have to buy another computer again because it has so many standard expansion slots!”
While the obvious answer has been stated (the IBM 5150) there are a few things that muddy up the waters here. There were a lot of differences between the XT class machines and AT machines, such as the addition of the real time clock and the second interrupt controller, as well as a different keyboard interface. Most software these days expects an AT architecture. The 386 was also the first processor to offer 32 bit registers, which most software these days depend on also. The PS/2 added the mouse controller that was part of the same little microcontroller on the motherboard that the keyboard used for its interface. This has become standard on PC’s, but since the serial mouse is still supported you can’t say it’s a requirement.
A case might be argued that the first “modern” computer was a 386 with an AT architecture. Not at all coincidentally, this is the earliest type of computer that can run Windows 95, the earliest of the “win32” operating systems (95, 98, NT 4.0, ME, 2000, XP).
FYI Musicat - you couldn’t run XP on a 5150 because the processor is too limited. It can’t execute the 32 bit instructions like MOV EAX, <value> because it doesn’t have an EAX (32 bit) register, only an AX (16 bit) register. I did however attempt to convert an old 5150 style case to a Pentium by swapping out the motherboard (just so I could say I had the world’s fastest XT) but unfortunately the cache module hit the metal bracket on the underside of the disk drive assembly. Oh well.
To run XP on a 5150 you need the following: motherboard (make sure you find one that fits), ram, processor, video card, monitor, hard drive, CD ROM, power supply (the original PC power supply was something like 60W, nowhere near enough for a modern system), keyboard, and possibly a mouse if your system doesn’t have one. The only thing you can keep original is the case (and even that may need some work, as I have some vague recollection about the spacing for the adapter cards on the back being different). I’m not sure if XP will recognize the 360k floppy drive.
That is my suggestion
The first computer in our family was a Sol (ca. 1977). You can get a peek a some of its (and many others) components here.
As I recall, our model came with a standard 8K. The operating system used just over 4K. You could upgrade to 16K for four hundred bucks (appx). We used a tape deck to load programs onto it. Ah, the good old days.
For some reason, I thought the first PC, or at least first popular PC was the Commodore Pet, in 1977…
Hey, I have a Sol myself. Built it from a kit in 1975 or thereabouts. I still have it, it’s sitting in a corner of the room about 3 feet from me. I fired it up recently, it still works, except the keyboard is shot. There’s a guy who sells keyboard refurb kits for about $100, or he’ll refurb it for you for an extra fee. I’m looking for his address, I think I’ll get this machine back up and running fully.
I never could afford a disk drive so I have everything on tapes. I heard of some people who experimented in converting their old data tapes to .WAV files and burning them on CDs or even making mp3s. That way you can restore weak tapes, store and file them, and then squirt them over an audio port to the old CPU. I get a laugh out of the idea of using my huge Mac setup to feed 300baud audio data to an 8080A micro. ha…
But as to the OP, the first use of the term Personal Computer I know of was the Apple 1. There were other companies that used this term, like the SWTPC, Southwest Technologies Personal Computer. I’m pretty sure these far predate the Altair’s usage.