Lunduke
News • Science & Tech
Quick and Dirty: The story of 86-DOS & MS-DOS
The hardware and nerdy details that led to the first release of MS-DOS.
January 19, 2024
post photo preview

MS-DOS is one of the most successful operating systems of all time — absolutely dominating the computer industry for years.

Most of us have heard the tales of how MS-DOS came into existence: How Microsoft purchased it from another company, and how Microsoft licensed it to IBM.

But what are the nerdy details? What is the background? What hardware inspired the development of that MS-DOS precursor… and what did those machines actually look like?

Let’s take a few moments to dive a little deeper into the history of how MS-DOS truly came into existence. To tell this story, we’ll need to go back to the mid 1970s…

1974 - The Altair 8800 & the S-100 BUS

Way back in 1974, the legendary Altair 8800 computer was being designed. And, as part of the system, the S-100 computer bus was designed.

The Altair 8800
 

Fun Factoids: The Altair 8800 was based on an Intel 8080 CPU clocking in at a whopping 2 MHz and sold, as a kit, starting at $439. That base model came packed with 1024 bytes of RAM. Yeah. You read that right. 1k. In order to run the new “Altair BASIC” — which was the first product of Microsoft — you first needed to upgrade to 4k of RAM… which would run another $264.

That S-100 bus — which allowed a number of peripheral cards (memory, drive controllers, etc.) to be inserted into, and used by, the computer — became the first expansion bus standardized across the computer industry.

In fact, usage of the S-100 became incredibly common among a huge number of homebrew computers built far and wide — being the defacto bus type until the IBM PC hit the scene in 1981.

Many of these computer types (using a variety of processors, including the 8080 and Z80) received ports of the CP/M operating system, developed by Gary Kildall’s Digital Research. CP/M was everywhere back then.

1979 - Seattle Computer Product’s S-100 8086 kit

Seattle Computer Products (SCP) (which, as the name would suggest, was based near Seattle, WA) produced a number of S-100 related products — including memory cards such as the 64k RAM board shown below:

Photo courtesy s100computers.com
 

Seattle Computer Products then expanded to produce boards and kits to build S-100 bus based computers using the Intel 8086 CPU (which had just been released by Intel).

SCP’s 8086 S-100 card. This is a later variant (1980 or 1981) of the original 1979 version.
 

There was just one teensy-tiny problem… there was no available operating system to ship with these S-100 based 8086 systems.

Initially these SCP S-100 8086 computers shipped with no full-fledged operating system at all.

But, instead, they worked with another local company — Microsoft — to bundle a version of their BASIC language. The result was known as “BASIC-86” and it was, essentially, a BASIC interpreter and editor, that booted from disk on the new SCP 8086 systems.

This wasn’t the only product that the two companies worked together on. Microsoft had also hired SCP to design their “Z-80 Softcard” for the Apple II platform.

 

This relationship — between Seattle Computer Products and Microsoft — would become critical to the entire computer industry.

Sales of the SCP S-100 8086 boards struggled due to the lack of operating system. Turns out most people want an OS to go with their computer. Who knew?

To remedy this problem, SCP encouraged Gary Kildall to port his wildly popular CP/M operating system to 8086 board (which Kildall had already been working towards anyway). Unfortunately the CP/M port was not shipping fast enough to meet the needs of SCP.

They needed an Operating System. And fast.

1980 - Quick and Dirty DOS

Seattle Computer Products did the only logical thing… they began building their own Operating System.

In April of 1980, Tim Paterson began working on exactly that. Armed with the manuals for CP/M, he began building his own “CP/M-like” operating system — from scratch — in assembly for their 8086 platform.

This effort was called “Quick and Dirty Disk Operating System”… or “QDOS” for short.

QDOS was incredibly similar to CP/M — as the design was done based on the CP/M manuals — and a key goal was to allow easy porting of CP/M software to QDOS. That said, it did differ in some noteworthy ways:

  • CP/M cached file system information, which could cause data loss if an update was not manually performed before a user removed a disk. QDOS changed this by doing disk updates on every write to the drive. This resulted in QDOS disk operations being slower than CP/M… but also protected against data loss.

  • Instead of CP/M’s file system, Tim used the FAT system that Microsoft created for the standalone BASIC-86 that SCP had already been shipping with their S-100 8086 machies.

Fun Factoid: The FAT (File Allocation Table) file system was developed by Marc McDonald — the first full time employee of Microsoft — and first used as the file system for “Microsoft Standalone Disk BASIC-80” (a bootable floppy for 8080 CPU’s that contained a BASIC interpreter). That was later ported to 8086 and was bundled with Seattle Computer Products 8086 systems.

QDOS required the SCP S-100 8086 systems, naturally, with a specific floppy drive controller: the Cromemco 4FDC, as pictured below.

Photo courtesy s100computers.com
 

By July of 1980, QDOS was functional — with roughly half of the outlined feature set. Then, by August, the famous EDLIN command was added.

Factoid time! The EDLIN program, a simple line editor, is the most enduring portion of this original version of QDOS. Lasting until this day, in various forms and ports, and being the primary text editor for MS-DOS up until the early 1990s. It was inspired by the ED commands of both CP/M and UNIX.

During the summer of 1980, the name QDOS was dropped (as “Quick and Dirty” isn’t the best product name) in favor of the, rather on-the-nose, “86-DOS”. A DOS. On the 8086 platform.

Bellow are a few screenshots of 86-DOS from the 1.0 version, which didn’t ship until 1981 (but still gives a good view of what it looked like back then):

COMMAND.COM and EDLIN
 
A DIR of an 86-DOS system

And, for the sake of posterity, here is the first part of the 86-DOS user manual for version 0.3. This is the very first published description — ever — of the OS that would later become MS-DOS.

At this point, Seattle Computer Products could begin bundling their S-100 8086 systems with the, now functional, 86-DOS.

Below you can see an advertisement of exactly that. A complete computer with an 8086 @ 8 MHz, 128k of RAM, the disk controller mentioned above… and shipping with both 86-DOS and Microsoft’s 86-BASIC. For a mere $3,349.

Ad for the SCP S-100 in the November, 1981 issue of Kilobaud Microcomputing magazine.
 

1981 - The Microsoft Agreement

Remember how Microsoft and Seattle Computer Products had worked together a few times already? Well, they were about to make an agreement that would change all of computing for decades to come.

Starting in November/December of 1980, Microsoft licensed a version of 86-DOS (version 0.3 to be exact) from SCP. This was a non-exclusive deal, meaning SCP could still sell 86-DOS and license to other OEMs.

Amazingly enough, a copy of one of that license — dated January 6th, 1981 — is now available so we can know the exact terms of the deal:

Document copy, courtesy Archive.org
 

That’s when things really took off. At an almost lightning speed.

Just a few short months later — in May — Tim Paterson left SCP and started working directly for Microsoft. His job: to port 86-DOS to the new IBM PC, which had an 8088 processor.

Then, in July of 1981 (just two months later), Microsoft purchased 86-DOS — in entirety — for an additional $50,000 (over the $25,000 MS had previously paid for a non-exclusive license). It was now Microsoft’s to do with as they please… and the original developer now worked for them.

That very next month, in August, Microsoft officially licensed MS-DOS to IBM… who then bundled it with their new IBM Personal Computer (the famous model 5150)… renamed “PC-DOS”.

Something wild to think about: Consider the timeline here.

  • The IBM 5150 PC was announced on August 12th, 1981.

  • The deal between Microsoft and IBM — for MS-DOS, renamed to PC-DOS — was finalized… that same month.

  • Microsoft didn’t actually own MS-DOS… until a few weeks before that.

  • … and Microsoft didn’t even have the developer (Tim Paterson) working for them until two months before that.

That’s right. One of the most important business deals in computer history… came together in a matter of just a few short months… with only days to spare.

Epilogue

There is oh-so-much more to this story. Too much to tell in one sitting.

  • MS-DOS would go on to absolutely dominate the computer industry and set the course of Microsoft for decades to come.

  • That version of CP/M that Seattle Computer Products wanted (before they gave up waiting and built QDOS)? It eventually shipped in November of 1981. CP/M was this close to being shipped with the first IBM PCs. You can mark that moment as the point when CP/M lost its position of market dominance.

  • The relationship with IBM and Microsoft would be a wild and rocky one — involving PC-DOS, OS/2 and many other products over the years.

  • Tim Paterson would end up working at Microsoft, multiple times, on several versions of DOS as well as Visual BASIC.

Fun personal anecdote: As a young man in the 1990s, I started working at Microsoft. One day, it occurred to me: “I wonder if Tim Paterson still works here?”

 

So I looked him up and, turns out, he did. In a building just around the corner from the one I was working in. So I did what any presumptuous, nerdy 19 year old would do… I sent him an email. One where I sounded like a giddy fanboy. Because that’s what I was.

 

Tim was gracious and kind. Taking time out of his schedule to chat with a fan of his work. While we only spoke on a few occasions, those moments meant a great deal to this young nerd.

community logo
Join the Lunduke Community
To read more articles like this, sign up and join my community today
6
What else you may like…
Videos
Podcasts
Posts
Articles
February 13, 2025
Fedora's Code of Conduct: 200 Day Response Time, Only Protects You if Red Hat Likes You

Lunduke tests Fedora Linux's Code of Conduct. The results are just as ridiculous as you'd expect.

00:17:20
February 13, 2025
Lunduke Journal's New Self-Hosted Forum, Telnet BBS

So many ways to enjoy The Lunduke Journal now -- X, YouTube, Rumble, Substack, Podcast & more -- plus two new (self-hosted) ways to interact with the community.

More from The Lunduke Journal:
https://lunduke.com/

00:17:09
February 12, 2025
Codeberg Announces "Fight Against Far-Right"

The Git source code hosting organization, in response to anonymous spam, declares war on "Right-Wing Forces", encourages others to do the same.

00:17:56
November 22, 2023
The futility of Ad-Blockers

Ads are filling the entirety of the Web -- websites, podcasts, YouTube videos, etc. -- at an increasing rate. Prices for those ad placements are plummeting. Consumers are desperate to use ad-blockers to make the web palatable. Google (and others) are desperate to break and block ad-blockers. All of which results in... more ads and lower pay for creators.

It's a fascinatingly annoying cycle. And there's only one viable way out of it.

Looking for the Podcast RSS feed or other links? Check here:
https://lunduke.locals.com/post/4619051/lunduke-journal-link-central-tm

Give the gift of The Lunduke Journal:
https://lunduke.locals.com/post/4898317/give-the-gift-of-the-lunduke-journal

The futility of Ad-Blockers
November 21, 2023
openSUSE says "No Lunduke allowed!"

Those in power with openSUSE make it clear they will not allow me anywhere near anything related to the openSUSE project. Ever. For any reason.

Well, that settles that, then! Guess I won't be contributing to openSUSE! 🤣

Looking for the Podcast RSS feed or other links?
https://lunduke.locals.com/post/4619051/lunduke-journal-link-central-tm

Give the gift of The Lunduke Journal:
https://lunduke.locals.com/post/4898317/give-the-gift-of-the-lunduke-journal

openSUSE says "No Lunduke allowed!"
September 13, 2023
"Andreas Kling creator of Serenity OS & Ladybird Web Browser" - Lunduke’s Big Tech Show - September 13th, 2023 - Ep 044

This episode is free for all to enjoy and share.

Be sure to subscribe here at Lunduke.Locals.com to get all shows & articles (including interviews with other amazing nerds).

"Andreas Kling creator of Serenity OS & Ladybird Web Browser" - Lunduke’s Big Tech Show - September 13th, 2023 - Ep 044

FUTO is putting on a “Don’t Be Evil” event during SXSW.

March 15th. Myself. Louis Rossman. Andreas Kling.

It’s going to be nerdy. And, guaranteed, it’s going to be talked about.

https://partiful.com/e/iI0zo1ewEu0YP4ii5XWF

post photo preview
post photo preview
post photo preview
February 13, 2025
For February: 50% off Subscriptions, 50% off DRM-Free Downloads, Lifetime Subscriptions available

2025 is off to an amazing start for The Lunduke Journal.

The number of people getting their Big-Tech-Free Tech News from The Lunduke Journal is shooting through the roof. Subscriptions (of every kind) are soaring.

And The Lunduke Journal is now available on a wide variety of platforms — with our core community area now consolidating on our own, self-hosted forum (which is exclusively available to subscribers).

With the tidal wave of new people — many of you wanting access to the new, exclusive Forum — I want to make it as easy as possible for everyone to become a part of what we are doing. Time to do something a bit crazy. Massive discounts on subscriptions (I mean… huge). For the entire month of February.

Yup. The whole gosh darned month.

If it’s February, the discounts below are all available. Choose whatever works best for you. Then feel awesome about supporting truly independent Tech Journalism.

50% Off Yearly Subscription:

50% off a Yearly subscription to The Lunduke Journal via both Locals and Substack. (This includes full access to the community Forum.)

That’s $2.25 per month. Pocket change.

50% Off DRM-Free, MP4 Downloads:

Want to be able to download every show The Lunduke Journal releases (and watch them on whatever device you like)? Yeah. You can do that. For 50% off.

Note: This DRM-Free download option does not include access to the Forum. This option is strictly for downloading the episodes.

The Famous Lifetime Subscription:

The "World Famous Lunduke Journal Lifetime Subscription" is exactly what it sounds like. Pay once and get full access to The Lunduke Journal. For life. A great way to support Big-Tech-Free Journalism.

(This includes full access to the community Forum.)

New Lifetime Subscriptions are available, for $200, from now through February 28th.

The Lifetime Subscription can be obtain via Locals, Substack, or using Bitcoin. All three options work great and are super easy.

How to get a Lifetime Subscription via Locals:

  1. Go to Lunduke.Locals.com/support.

  2. Select "Give Once".

  3. Enter "200" into the amount field.

  4. After checking out, Lunduke will toss you an email once your account is set to full lifetime status. (This usually happens within a few hours.)

How to get a Lifetime Subscription via Substack:

  1. Go to Lunduke.Substack.com/subscribe.

  2. Select the “Lifetime Subscription” option.

  3. After checking out, Lunduke will toss you an email once your account is set to full lifetime status. (This usually happens within a few hours.)

If you would also like full, Lifetime access to Lunduke.Locals.com (which is included):

  1. Make a free account on Lunduke.Locals.com.

  2. Email “bryan at lunduke.com” with the email address you use on both Substack and Locals (can be different email addresses).

  3. Lunduke will toss you an email once your account is set to full lifetime status on Locals.

How to get a Lifetime Subscription with Bitcoin:

And, finally, you can obtain a Lifetime Subscription via Bitcoin. Save a few bucks with this option, as Bitcoin processing has fewer fees associated with it.

bc1qyjakve8fywm8pz2v99v57yhjj0vzr2vjze6fcq

  • Email "bryan at lunduke.com" with the following information: What time you made the transaction, how much was sent (in Bitcoin), and the email address you use (or plan to use) on Locals.com.

The Lunduke Journal would not be possible without your support. Every subscriber, of every type, makes a massive difference in bringing Big-Tech-Free Tech Journalism to the world.

Thank you.

-Lunduke

Read full Article
February 09, 2025
post photo preview
The Great Tech Demographic Survey of 2025

There are a lot of questions we don't have good answers for.

  • Do Trump voters prefer EMacs or Vi?
  • Who is happier with their life... people who use Tabs or Spaces?
  • Does your age impact your choice of Web Browser?
  • Who is more likely to support censorship... Rust Programmers or C Programmers?

Do you know the answers to those questions?  No, I don't either.

Let's find out.

The Great Tech Industry Demographic Survey of 2025

This survey is massive -- containing questions on everything from Operating System preferences to religion and politicsProgramming languages and... workplace discrimination.  It even gets into Cryptocurrency and Text Editor preferences.

Seriously.

  • All answers are 100% anonymous (no account is needed), no email address is collected.
  • All questions are optional (only answer the ones you feel comfortable with).
  • The questions are all presented in random order.
  • All of the (anonymous) results will be published.

The 2024 edition of this survey (last year) was taken by over 7,200 people across the entire IT industry -- an absolutely massive sample size (larger than most US Presidential Election polls).  For this new 2025 survey... we're aiming even higher.

Are you a computer nerd?  Do you work in the IT industry?

Set aside a few minutes and take the 2025 survey.

Then tell everyone about it.  The more people who take the survey -- across as many companies and communities as possible -- the better the data will be.

Read full Article
February 03, 2025
Fund Indie Tech Journalism. Lifetime Subs & Discounts available for 48 hours.

February is upon us! And — would you look at that — thanks to all of you, The Lunduke Journal is already fully funded through the end of February!

That means: We can continue to have zero sponsors, zero advertising and, even more importantly, zero influence from Big Tech.

Now. How amazing would it be if The Lunduke Journal could reach our funding goals through the end of March… almost two months ahead of time? Pretty freaking amazing. And absolutely doable.

Let’s do it.

Through Tuesday (February 4th), we’ve got a handful of discounts on Lunduke Journal subscriptions. Take a look. A huge thank you to everyone who has already subscribed — you make this all possible.

Every penny goes towards keeping truly independent journalism alive.

Lunduke Journal Discounts

For the next 2 days (through Tuesday, February 4th), in addition to regular subscriptions, you can grab two limited discounts:

  1. Discounted Lifetime Subscriptions (scroll down for details)

  2. DRM-Free, MP4 Downloads for 2024 & 2025 (combined) for 55% off.

There many ways to support The Lunduke Journal. Choose the option that makes you smile. It’s all listed below.

Where to grab a Monthly or Yearly Subscription:

These are regular price. But still awesome.

Lifetime Subscription Details:

  • Pay once, full subscription for life (on Locals, Substack, or both).

  • Available only until Tuesday, February 4th. Then the Lifetime Subscription option goes “back in the vault”.

  • Can be purchased via Locals, Substack, or with Bitcoin. Chose whichever works for you. Scroll down for steps.

Where to buy a DRM-Free, MP4 video yearly download pass:

Want to be able to download every show The Lunduke Journal releases (and watch them on whatever device you like)? Yeah. You can do that.

The Famous Lifetime Subscription via Locals:

The "World Famous Lunduke Journal Lifetime Subscription" is exactly what it sounds like. Pay once and get full access to The Lunduke Journal (with all the perks of subscription on Locals). For life.

New Lifetime Subscriptions are available, for $200, from now through February 4th. Then this option goes "back into the vault".

Here's how to grab one of these coveted bad boys for yourself:

  1. Go to Lunduke.Locals.com/support.

  2. Select "Give Once".

  3. Enter "200" into the amount field.

  4. After checking out, Lunduke will toss you an email once your account is set to full lifetime status. (This usually happens within a few hours.)

The Famous Lifetime Subscription via Substack:

You can also snag a Lifetime Subscription via Substack:

  1. Go to Lunduke.Substack.com/subscribe.

  2. Select the “Lifetime Subscription” option.

  3. After checking out, Lunduke will toss you an email once your account is set to full lifetime status. (This usually happens within a few hours.)

If you would like full, Lifetime access to Lunduke.Locals.com (which is included):

  1. Make a free account on Lunduke.Locals.com.

  2. Email “bryan at lunduke.com” with the email address you use on both Substack and Locals (can be different email addresses).

  3. Lunduke will toss you an email once your account is set to full lifetime status on Locals.

The Famous Lifetime Subscription (with Bitcoin discount):

And, finally, you can obtain a Lifetime Subscription via Bitcoin. Save a few bucks with this option, as Bitcoin processing has fewer fees associated with it.

  • Make sure you have a Lunduke.Locals.com account (a free account works just fine).

  • Send $190 worth of Bitcoin (or more) to the following address:

bc1qyjakve8fywm8pz2v99v57yhjj0vzr2vjze6fcq

  • Email "bryan at lunduke.com" with the following information: What time you made the transaction, how much was sent (in Bitcoin), and the email address you use (or plan to use) on Locals.com.

Once again, thank you. The Lunduke Journal would not be possible without your support.

You rule. Seriously.

-Lunduke

Read full Article
See More
Available on mobile and TV devices
google store google store app store app store
google store google store app tv store app tv store amazon store amazon store roku store roku store
Powered by Locals