The IBM PC 5150 - the world's most influential computer

This is the story of the first IBM PC - your current home or laptop computer is almost certainly a direct descendant of this machine. Today, nearly 40 years after its introduction, modern PC's are used for everything from the kinds of business applications the system was originally designed for, to scientific work, to high-end gaming. But it all started back in 1981 with the IBM 5150.

If you're looking for a more personal take on this computer, watch for my upcoming review of this IBM 5150!

Some credits for some of the images and other things used in this video:

And on Twitter:

[ModernClassic]

Hey guys - one quick clarification about something that's getting a few comments. In the video I say that the PC was 2-4 times faster than its competitors at tasks important to businesses. Keep in mind that I was not comparing clock cycle vs. clock cycle of the CPU alone against only certain other CPU's (I showed more than CPU speed in the chart); I was comparing overall performance in real-world tasks. As we all know even today, there's more to a computer than just its CPU, and the fact that the PC had a very advanced graphics subsystem, support for massive amounts of RAM (for the day) that reduced or eliminated the PC's need to access a disk while within an application, a fast system bus, math co-processor support and a faster floppy and hard drive interface than its competitors, made it much faster overall than those machines at tasks important to businesses (for example, large spreadsheets or relational databases).

Of course, that doesn't mean that some of the machines on my list weren't better at certain other tasks - I'm a big Atari 8 bit and Apple II fan, personally (and am an Apple II owner since 1985), and would choose either of those machines to play games on before the early PC. In fact, I actually made that choice - I chose my Apple IIc at a time when the PC AT was already available!

[daffyduck]

I'm a former electronics engineer who was among a handful of people who, back in the early 1980s, had designed the first IBM-compatible microcomputer system (now termed a "personal computer"). I prepared by studying the circuitry of IBM PC and while not all was apparent I had deduced a lot of things from it. It wasn't an exact copy by any means but the machine worked and designed with higher speed, higher memory, and more expansion slots (like an XT version). In those early days engineers had to design from scratch with hundreds of digital circuit chips, (everything from the motherboard, DRAM interface, hard disk drive, etc), unlike today's much easier VLSI (Very large Scale Integration). The product went into high production and was distributed to 7-11 stores throughout the US. There was no parade for me, only a big recognition clap from my boss and fellow engineers. They didn't know that I didn't do it entirely out of the blue. These days in retirement I tune pianos.

[BobSmith-ghwj]

My Dad still has his IBM 5100 with the printer that came with it from 1975 - it cost $36, 000 and the printer cost about the same. To this day it is still fully functional.

[skril]

My father bought an IBM 5150 when it first came out and we still have it to this day.

[Zanth]

My Dad worked for IBM starting in the 60s . Started in working on mainframes and in the late 70s was promoted to systems engineer. they gave him a 5150 . He also wrote manuals for them.

[danielt.]

Fresh out of college with a degree in computer science I wrote an application for Estate Planning that analyzed inheritance taxes, multiple strategies, outcomes, and other factors targeted at high net worth customers for a local insurance agent for Mass Mutual, the insurance agent then positioned this application and some extensions to Dunn and Bradstreet. My first paid gig as a programmer and all on a brand new IBM PC which I never had access to a desktop computer, I had to learn the OS and IBM Basic language. Dunn and Bradstreet loved the app and acquired the insurance agent and his company with the estate planning app. I had gas money and something to put on my resume and made my car loan payments.

[CattoRayTube]

I've watched a few IBM PC retrospectives, and this would have to be the best. Very well presented and paced, with content, asides, and comparisons not found elsewhere.

[garyclouse]

A few historical notes:
The design team at Boca Raton initially studied the successful micro computers on the market to co-develop the their marketing strategy along with the product design parameters.

the design target was a desktop computer that would appeal as many markets as possible, and their design showed this philosophy
At the time the CP/m operating system dominated business computing and a large library of third party software. CP/M ran primarily on inlet 8-bit processors (8080, 8085) and some 8080 compatible chips from Zilog (Z-80). Intel had introduce the 8086 design which was source code compatible with the older 8080 to simplify the porting existing 8-bit software to the 16-bit processor. However, the cost of memory chips would have greatly increased the price so they decided to use the 8088 CPU, an Intel transitional design that was completely machine code compatible with the 8086, but used an 8-bit data path.
The PC design team noted that computers in the home and educational markets were expandable, with the most successful computers in the market sector have a large variety of third party hardware, so in a break from IBM's tradition closed business model, they specifications and designs to encourage third-party hardware development, but decided to use copyrighted bios ROMS to provide legal protection against copycat (clone) machines. The idea was to use a propriety OS that would only work after authenticating the bios roms.

It's fairly certain that IBM intended on purchasing CP/M86 from digital research, but when they went to make the deal, Digital Research would not agree to IBM's NDA clause in their licensing. However, an IBM executive had learned of the existence of a clone of CPM86 through back channels owned by a small software company calling itself Micro-Soft and a deal was made for a version of the 86-dos operating system with the authentication code to be named PC-DOS

Micro-Soft's co-founder, Bill Gates, whose father and grandfather were corporate lawyers took advantage in a huge loophole in contract law and after providing PC-DOS to IBM and renamed
and produced a modified version of 86-dos without the authentication code called MS-DOS

For the home market, a non disk PC would boot into Microsoft Basic from rom, and rom basic programs could be save and loaded with a standard portable cassette recorder, but there was no way to use the cassette port or even use the cassette basic program after adding a floppy controller.

The original base price of the PC did not include a display adapter.For home use the color graphics adapter was offered for use with a tv, and for business a monochrome monitor and the business graphics adapter was offered

[thethirdcell]

I was the Contract Specialist for IBM Corporate Component Procurement and negotiated the IBM PC component contracts from 1980 thru 1984. It was a wild ride with contracts that equal $800 million dollars in todays dollars. I consider that time in my career to be the most satisfying, but also the most taxing!

[JMacQ]

I worked in the computer lab of my university from 1994 until graduation. We had a 5150 working as the print server/spooler for the whole lab. Somehow, it was able to handle print requests from banks of both Classic and PowerPC Macs, and from Windows computers (probably 60 in total), and I never remember it once crashing or having any kind of mechanical failure. That 5150 was the first computer we'd start up in the lab early in the morning, and the last one that we would shut down at the end of each night. It wasn't even upgraded with a hard drive (and the required higher-wattage PSU). That was the only computer type in the whole lab building that I never remember having run into a problem with. I wish the hardware and software will still made to that standard.

[pim]

When I started working the company got 2 IBM's, now I am almost gonna retire ... this vid gives me good memories ...

[TheRealLaughingGravy]

Great video, a really nice presentation. I'm glad you spent a little time praising the PC's keyboard. It's easy to forget now, but at the time, keyboard quality on personal computers varied greatly, and having a keyboard that just "felt right" was a key selling point for me and a lot of other people. The PC's keyboard was a delight to type on (as was the IBM Selectric's, which you also mentioned). It was just so _satisfying._

[jamesross]

I was 18 in 1981 and that is the year i bought a TRS-80 Color Computer. But I recall reading all about the IBM PC in Byte magazine. My first PC/XT clone was in 1988. Great memories great review.

[davedumond]

A modern classic indeed. My early career experience exposed me to the IBM PC architecture. While employed at NCR 1978-1984 I worked on their PC XT clone as well as a 3270 plug-compatible emulation system. The opportunity was there because IBM couldn't keep up with demand for the products. NCR separated themselves in the PC clone market by using amber text screens and DIN-standard low profile keyboards, which were excellent. I remember purchasing an NCR PC clone before leaving the company in 1984 for the employee price of $1500. Great video, thanks for the memories!

[jerseybob]

Thanks for the stroll down memory lane. I worked for IBM for 37 years. My first PC was a PC XT running DOS. Then a PC AT running DOS but with green screen mainframe access. Then a PS2/70 and then a PS2/80 and an L40/SX all running OS/2. We finally switched to laptops with Windows. It was quite a ride.

[alandouglas]

Great video. It brings back very fond memories for me as I was a PC specialist for IBM New Zealand back in the 80's. Although being trained on the PC Jr, New Zealand never released the product to the local market. Hurrah! We, along with Australia and Japan, got the IBM Japan developed PC JX. This was a much better designed version of the PC Jr, although not much better! It didn't last long.
I actually received the first ever PC XT into the country and I can remember saying to one of my colleagues: "A 10 MB hard disk! No one will ever fill that up."
How wrong was I!

[geraldloudermilk]

Great video. I worked at IBM Boca from 1984 till 1994. When I started we were making PC's 24/7 you could work as much as you liked. It was a good time.

[josephsmith]

I am computer enthusiast, and spend so much time looking through the PC Magazine archives in Google Books. All the information you have is just pure gold...

[mjordan]

Memories... I was there for (almost) the whole ride - my first computer was a Mod I Level 2 TRS-80 with 4K of RAM. What IBM brought to the table was legitimacy. What had been a geek's toy, now became a legitimate business machine.

[willrsan]

This history is utterly fascinating because my dad had one of the original IBM XT "portable" machines which was my formative computer experience and now I am watching this on a descendant of the original PC. The keyboard I am using came with a NEC server and is obviously a direct clone of the IBM model M keyboard in layout and color. As to the PC I am using - it is running Windows 10 ( descended from MS DOS) has an Intel CPU ( a XEON X5650) has an ASUS ROG motherboard with Intel X58 chipset, all 10 year old tech but still works great - basically a mix and match of components conforming to some loose standard. If I could travel back in time to the late 70s and early 80s I would tell those early computer designers from Commodore, Atari, Apple and whoever that a successful computer has to be open and expandable and upgradeable in order to be successful as I am from the future and have seen what works. The PC lives on!