MS-DOS has been Open-Sourced! We Build and Run it! 

I'd love git to just stop messing with these, you can set it up so but defaults are just destructive

Came from mainframe environment where file system had records. Took a while to get used to the idea that special character(s) determined records.

It's of note, though, that MacOS has used Unix line endings since 2001 (when they released X). It's only the classic Mac releases that use carriage return for line endings.

Good to hear that you can laugh about it. I cry about it on a weekly basis. Having said that, there are even worse things out there, like case sensitivity and the infamous special syntax regarding NULL in SQL.

@@nkronert I feel your pain. It's 2024 and we still can't have simple select statement to display national characters correctly.

We all want to see MS-DOS 7.1. Released as part of Windows 98. With long filename support and Fat32. That was the Ultimate DOS. (You do have to Hexedit the Win98 logo's out of it.)

@@retinaquester you didn't want to go all the way to the rather embarrassing Windows ME MS-DOS 8?

@@koopa2k I thought they took peaces out of that version of DOS. Until 7.1 it keeps getting better.

@@retinaquester I think you can just use the Logo=0 parameter in MSDOS.sys in Win98's DOS

I doubt Bill Gates will still be alive 6 years from now. Who's going to hold the keys to the castle after he's gone? Sooner or later it gets passed on to someone willing to sell it off or give it away because they have no interest in "grandpa's old junk" in a shoebox in a closet somewhere.

It's kinda crazy that I've been experimenting with DOS since I was 14, know the installation like the back of my hand, and now I'm watching the dude who made that possible. I wasn't even born in the DOS era, I just like older OSs... (Shoutout to WinWorld for keeping ISOs/Floppy images of DOS for free...)

he is like the Archimedes of computers

Nah, that's ARM and used RISC OS 🤪

@@TonyWhitley I wanted to call him Plato but that existed too as a computer and Einstein too

Thanks for the kind words! I do hope they preserve the first program I wrote: 10 PRINT "DAVE" 20 GOTO 10

Haha, I used WATFOR and WATFIV Fortran in South Africa way back when...

Honeywell was implementing ML into industrial food processing units at a huge scale before anyone even knew what ML was. I saw it with my own eyes 😳😳 and this is a pattern with them. Take an emerging tech or innovate such tech, implement it in its simplest form on a massive scale.

The obscure Centurion minis of that timeframe had a "Library" system. A library was a collection of files, rather like a directory, but I believe they weren't nestable. The Centurions are being restored and explored by @UsagiElectric - a wonderful retro tech channel.

just curious. do you still view Unix based architecture a toy nowadays? is there an evolution of Honeywell or equivalency? i'm a dummy and i'm being genuine.

Sometimes it is weird as a developer to imagine people having roughly twice the experience of your age.

You mean skynet and the rise of the machines. " there is good money in killing people" - Bob Dylan - masked and anonymous

DeLorean just came out with an electric. Awesome looking ride.

One point twentyone Jiggawatts!?!?!?!

QDOS quick and dirty os. DOS. Dirty OS

@@aaronposey7003 Dirty Old Sock.

Not only is "MZ" on DOS executables and earlier Windows executables, it is on modern PE Windows executables too _and_ all-platforms UEFI payloads (I was rather surprised and amazed, when working to help make the firmwares for a modern _ARM_ computer system - a Rockchip RK3588-based board called the Firefly ITX-3588J - that the UEFI payloads for the Linux[!] kernel had good ole "MZ" at the beginning!). The reason for this is not just legacy cruft; it's so that it can be abortively loaded by an old DOS/Windows system to spit out an error that it is not compatible with it :D

So Mark Zbikowski is the apex level digital tagger of all time then. He got his tag on the entire world. 😂 genius move

the fact that they chose to relese 4 is utterly sick. It's decades old and they still won't give us full freedom over our own systems, even massively outdated ones.

I had no idea, that's really cool. Thanks for sharing.

At least all the older files did. (COFF format if memory serves me right.) The newer ones use the Portable Executable format instead, where you find "PE" in the first few bytes of the file instead of "MZ".

"Every man dies two deaths. The one with his last breath, and the one with the breath of the last time someone says his name." Or something like that.

@@benhetland576 We both were partially incorrect. A PE format file actually includes everything we've mentioned. PE is based on the Unix standard COFF format, contains a 4-byte magic "PE\x00\x00" but also contains a stub DOS program (the one that just prints "This program cannot run in DOS mode") and that stub is right at the start, and still contains the "MZ" magic. So effectively PEs still contain "MZ" at the very start, with the "PE" magic coming later in the file.

@@YdenPL tnx for checking. Yes, and the MSDOS stub also imbeds another feature inherited from the pre-DOS era: the Ctrl-Z end of (text) file marker. So if you TYPE file.exe only this text, which is at the beginning, will print and not the rest of the binary "garbage".

Yes, i was disappointed when the more "technical manuals" in the 5.25 binders were not provided after IBM DOS 2.0 i relied heavily on the information there - Just as i did the OS Data Structures and Systems Manuals for the 360 / system 3 / system 7 / System 34 & 36

I think I still have a copy of Undocumented DOS on my bookshelf! Turbo Assembler and Turbo C were *so* much better than their Microsoft equivalents. They were faster and generated smaller and more efficient executables. Turbo Debugger was also an excellent tool.

I mentored a recent college graduate back in the DOS days who, when he was a poor college student, had a computer, but only enough of DOS to boot the machine. None of the utility programs that come with DOS were included. He did, however, have Turbo Pascal, so he wrote his own utilities. He had what I came to call a "strangely shaped" knowledge of DOS. He knew nothing about the collection of utility programs that came with DOS, that the typical beginner *would* know, but he was very familiar with DOS internals, which he had to learn in order to write his own programs.

@@BenEColeman That's interesting. I worked for a company called DNA (Device Network Architecture) Networks, Inc. At the time (early 80s), they developed a PC networking system before such a thing existed around the early days of PCs and DOS. This is long before Ethernet. They started this before companies like Novell and Lantastic were even a thought in anyone's mind yet. They had their own hardware and cabling, and developed their own software around this, which had file and record locking done their own way. They wrote their own BIOS chips for the 1st PCs, and their network code lived in them. All of this had to work on PCs with as little at 128k of memory. It all started out as a way to share expensive printers on more that one PC. Honestly, what they did was quite an achievement in its day. What was particularly interesting to me while I worked there doing tech support was, none of the devolvement tools they used were from the outside world. They created their own in house Assembler and Linker, several BASIC compilers, a C compiler, an in-house Debuger that was network aware. All of these tools were wrote using the Assembler they wrote. I used to joke around with them as to how they wrote the Assembler before anything else, and they would talk about the "chicken and egg" thing. LOL I am not sure I ever got an answer to that for them. In any case, working there was a fantastic learning environment, and I learned to use all their tools, which unfortunately was pretty much useless in the outside world where they folded and I need to secure another job. In my opinion, the things they did were better than what the competition (Novell and Lantastic) was doing, that eventually put them out of business. But that's the way it goes. Just because you created something better, doesn't mean you get to become the standard. Anyone remember Wordstar? Those awful commands are still in every modern piece of word processing software today.

@@BenEColeman That's interesting because I worked for a company, DNA (Device Network Architecture) Networks, Inc., that created a PC networking product, before there was such a thing. They networked PCs together mostly, at the time, to share expensive printers and scanners, to reduce the cost of needing one attached to each PC in an office. They did it their own way, long before Ethernet and other types of networks (Novell, Lantastic, Ect) were even a thought in anyone's mind. It was back in the early days of the IBM PC and PC-XT, when the first versions of MS-DOS and PC-DOS were just getting started. The developers use their own in-house developed Assembler and Linker, their own versions of BASIC and C compilers, and an in-house developed Debuger that was network aware. They used nothing from the outside world. I remember once asking how they created their first Assembler before they has anything else, and was told a story about the "chicken and egg". LOL I'm not sure I ever got any sort of real answer. In the early days, all this needed to work on PCs that had 128k of RAM, and they wrote their own BIOSs with all the network code in them. As a side note, supposably they were sued by IBM for copying their BIOS code, and the developer printed out the source on a stack of green bar paper, and handed it to the judge and said "if anything is too close to their code let me know and I'll rewrite it". Take that with a grain of salt. That is the way it was told to me. They developed hardware and cabling as well. Remember, no Ethernet yet, so again, they did it their own way. While working there, I was around some really smart people, and learned a lot. I was a tech support person that did troubleshooting and minor code fixes and wrote utilities. As I learned to program using their tools, I came to realize, when the company ultimately folded due to competition from other companies that started developing networks (Novell and Lantastic), that my skills learnd there were unusable any place else unfortunately. It was an interesting time in my life, that I learn to appreciate later, and started to learn just how ahead of their time they really were. It is unfortunate that just because you have something that is better than the rest, it doesn't mean it will become the standard. Remember WordStar? Those awful commands are still in almost every modern word processor. I'm glad I got to tell there story again.

Same.

It was a common old school methodology

This kind of tinkering, before google, was a huge part of my youth. And when getting things to actually work (or fix what I’d broken) was the greatest feeling.

I think fdisk was able to write the required boot sector (which I think is hardcoded 512 bytes) so you could have checked how it was implemented if you didn't want to use the shortcut to use official boot disk to capture the image. Of course, without MS-DOS counterpart of POSIX "dd" command, writing the 512 byte image the boot sector might be a bit complex.

​@@MikkoRantalainen now that it's open source, you can certainly make MS-DOS POSIX-compliant ;)

wow, DR-DOS, now there's a name I haven't heard in a long time...

I always ran into trouble trying to read a 360K disk that had been overwritten with a 1.2M drive.

Uh, I'm young, I don't remember this. Always had 1.2M 5.25" drive and 720k 3.5" at least. If I don't count floppy attached to Sharp MZ-800. Brings back some memories when best PC games were F-15 Strike Eagle, Grand Prix, Lotus and the rest were few kilobytes games such as AlleyCat or Sopwith inferior to games on ZX Spectrum.

Came here to write this exact thing.

This is why I used one of those cassette bulk erasers when doing that.

@@pavelperina7629 There was a corresponding problem the other direction with 1.2M diskettes: you could read 720k diskettes on a 1.2M drive, but if you took a 1.2M diskette that had been formatted and used before, reformatting it for 720k would not produce floppies that could be read on a 720k drive, for the same track width reasons.

I love these imperfections. It shows Dave is human, and it's like Easter eggs for us watchers.

It's free engagement and quite clever

Similarly I recall going from MS-DOS 3.1 to 5 without ever seeing 4.

We used these model 95 bad boys around 1993 or so for OS/2 & SQL Server backends, when IBM was also peddling their God awful SCSI RAID solutions. They had this feature where multiple drives would fail to start on cold boot, rendering the RAID invalid. The IBM engineer was called, he used the hammer in his toolkit to tap the drives to unstick the parked heads. The RAID config was stored in battery backed RAM on the HBA rather than across (or as well as) the drives... which was great until the HBA failed. OF course, there was no means to backup the config. That was the start of the death of IBM, we switched to Compaq. When your RAID solution is less reliable than a random bunch of disks, it's time to throw in the towel.

I'm from the same era! You learned a lot about computers at that time from tinkering around, and you had to tinker a bit to get software, games, or new hardware working! It was an exciting time to be in.

@@lophilip -- For some, it was aggravating as all get out.

@@lophilip Remember trying fix all the IRQ conflicts so your mouse, modem, sound card, and CD-ROM could all work at the same time? Ahhh yeah, those were the days. Had to get the modem going so you could log into the local BBS's! I still remember how much I loved my first modem (Supra 2400 baud). And don't ever forget the wonderful Telix terminal program! Yeah baby!

My PCjr with V20 CPU and 22NICE ran CP/M faster than my Xerox 820-II that had a Zilog Z-80. 22NICE was a Z-80 system emulator that could run on X86 CPUs *and* was able to activate the Z-80 hardware emulation in NEC's V20 and V30 CPUs so CP/M could run natively. 22NICE also set up the RAM and the rest of the system environment on a PC compatible for CP/M. I could use the same boot floppy on the Xerox, my PCjr and my 286.

My first modem was 300 baud. In 1 hour online downloading from a local BBS I could almost fill a 360k floppy drive before my hour was up! The good ole days!

3.3 was the sweetest spot. 5 was a close second. Edit: I'll be really really happy when MS releases either of these's source.

For a while in the late 1970's into the second half of the 1980's practically every personal computer with floppy drives had a DOS. The popular TRS-80 computers had TR-DOS. Heathkit computers had HDOS and so on.

I remember the Atari ST had TOS.

I always wondered why my portfolio had DOS2. Thanks!

@@JCCyC second that, 3.3 was quite "functional". However, I found that 2.11 was the last version not to mess with things behind the scenes, and instead do what you told it to. If you copied a disk, that's what you got, an exact copy. In ver 3 it started trying to be "smart", and for instance changed the disk label (identifier) on the copy.

Optimisation 101 The power of working directly from registers, and XORing a value with itself produces zero. No need for any more bus cycles to load an immediate value.

@@TomStorey96 Amen brother. I’d only use the c compiler if I knew ahead of time with the code it generated and agreed. My tattered and torn 8080 software reference guide (the one that told the number of clock cycles to execute) is still on my shelf and i know all these years later about half the 8080 instructions and the clock cycles the took. I still loved the 6502 better than 8080 instruction set.

I've found Turbo C to generate assembly that isn't too far off what I would write by hand. You can probably still do better by hand but I'll take the tiny performance hit for more easily readable code. :) I like assembly but I'm way more productive in C and will use it when I can.

Had it mainly in college.

If I may ask, what was your experience with CP/M like? Was it better, worse or about the same as DOS? Thank you for your time

@@greenrocket23 CP/M was pretty primative compared to DOS (especially later DOS with Unix like features), but at the time we took in stride. Never used CP/M+.

@@greenrocket23 Like Larry said. Primitive, simple. Source of "Int 21" and many of the command options. "DOS" copied "int 21" for "compatibility". It was the 80s, now I'm 66. There has been a lot of O/S and programming since. If I was a RETRO enthusiast, CP/M, CM/M+ with better directory structures, yeah, I'd play with that.

CP/M came first, in the 70's and worked on more primitive 8 bit CPU's. QDOS which turned into MS-DOS was based on CP/M in usage thanks to familiarity but took advantage of the more capable 16 bit 8086 and storage media at the time. Fat12 and on was a QDOS creation, CP/M used a more primitive method to keep track of used blocks on the drive, using a bit field, which scales poorly to larger drives.​@@greenrocket23

ever heard of unix? (leave me alone please i was just saying not trying to attack anyone like that one guy below did")

@@QohistUnix served a very different demographic

@@Qohist shooo shooo

@@Qohist It was ok, but VAX/VMS was better.

@@Juanguar i know ms dos was meant to be a desktop os unix was for servers but im just saying

In the 70s there was also IBM DOS for the System\360 mainframe :)

No, I'm sure this was 100% a company-wide mandate to reinforce the mentality that "the only DOS is MS-DOS." Microsoft was _fiercely_ competitive at this time, and not above sabotaging compatibility with "Not-MS-DOSes". The FUD, along with OEM strong-arming, was successful, though. I had _heard_ of alternative DOSes, like PC-DOS (which wasn't really an alternative, at least until version 5 or 6), DR-DOS, etc. ... but I had never seen them. The closest I got was an AST machine that, while it shipped with MS-DOS, used PC-DOS naming convention of ibmbio sys and ibmdos sys instead of io sys and msdos sys. I'm not sure why the discrepancy, and the disks were definitely labeled MS-DOS and had an MS-DOS setup program. Still, it was drilled into your head that MS-DOS was the only way to fly. That was NOT an accident.

Not to mention DR-DOS.

Microsoft really really hated digital research getting into their turf with DRDOS

@@fcassia I don't doubt it. I reckon that was the reason for wanting everyone to say "MS-DOS". Anyone can say they're DOS, but only Microsoft can say they're MS-DOS.

“Piqued”?

Yeah we refused to use 4.0. We stayed on 3.3 until 5.0 came out.

It was a bloated and slow.

@@stargazer7644 I remember that as well but considering there wasn't the internet it must have come from a review in some monthly computer magazine that I spent a fortune back in the day.

Boot menu was MS-DOS 6 fwiw

@@starfrost6816 I think that I was also using 4DOS a bit earlier than MS-DOS 6, and I first intruduced selective loading of programs in autoexec.bat back then, but I can’t remember for sure. It could just as well be on plain old MS-DOS 6 the first time I used boot menus… I definitely had multiple configurations much earlier with diferent boot diskettes for some games, or by copying config.sys and autoexec.bat pairs from a stash directory for the same purpose before the menus.

There is a html version online with a table of interrupt numbers. But the original is inside some zip files.

I bet that was ... fun ... to figure out. At least, the portions not well-documented and released to civilians.

i hope you fed your hungry DOS

Memmaker

Yeah, it's been too long to remember the details, but I do remember 4.0 was a turd and we didn't use it. We stayed on 3.3 until 5.0 came out.

@@stargazer7644 Funny how they keep releasing source code for the versions nobody liked.

@@mlegos When MS-DOS 4.0 was first released, MemMaker wasn't available yet.

Remember TSR (terminate and stay resident) programs? DOS wasn't multitasking, but this was a bit of a hack to get something running behind the scenes to provide background services. I don't remember what I was running, but I do remember fussing around with HIMEM.SYS and disk caching to try to clear up enough of that 640k because TSR's couldn't run in the high memory area or extended memory, as I recall.

Just like Windows.

Things were different. Instead of spending hours on the internet going into endless rabbit holes looking for solutions, you spent hours with jumpers, editing config.sys & autoexec.bat, and rebooting, on the impossible task of getting everything to work together.

​@@samuelhulme8347 one must be getting a really fat check from Microsoft to dare claim they love Windows in this day and age

I never hated it. I don't hate Windows either... I do hate what it's become, though.

@@jovetj ..said somebody, at every new release.

It could

I mean, FreeDOS has been a thing for over a decade.

It probably won't. At this point, the free software investment in reverse-engineering DOS is pretty much complete.

That ball alone, unless it's hollow, weighs more than a Finalmouse UltralightX.

One would think that writing 360k floppies should work if one were to write 2 adjacent tracks using an 80 track drive with the same data, but issues with sync timing accuracy and track length differences would probably make an even bigger mess than just writing every other track (on a virgin floppy).

It really isn't a problem at all, if you either start with unformatted diskettes or degauss them before formatting. The problems only happen when there is anything at all written on the odd-numbered tracks.

Just be glad the memory test prints progress. The early ones don't, so the computer doesn't print _anything_ on the screen (not even a flashing cursor) until the memory test has completed.

Nowadays it's Windows updates that slows down your boot and they won't be done in just a minute! 😂 (Not an issue on Linux though ^^)

Having to wait 1 minute with nothing on screen sounds oddly familiar to me as an AM5 user 😅

At the age of 7, my sister and I would sit down at the Vic 20. I would read and she would type. Only time we weren't fighting 😂

@@kstriclThat’s nice to hear. I hope you have more good memories.

@goodmanke - I've played around with ReactOS - it's great! Huge respect to the devs there, they've done great work! I also have great respect for the Haiku devs - they're doing awesome work too!

Don't forget TRS-DOS, MICRO DOS, and others for the TRS-80

Yes it works.

im glad to see your birth year did not dissuade you from learning the older OS, as i was born 20 years earlier than you, and i never felt like i could get into the stuff that was even a little bit older than myself. i have always wished i was born about 15 years earlier so that i could be around when software was starting to be made from scratch. to this day i still have no idea how it all works on the hardware level. i tried taking some computer courses but ultimately it felt too much for me to pick up. i can use and build computers just fine, but i will always have this missing chunk of information....

I wrote a TSR that hooked the open file int21 function and printed the file name on the last line of the screen so that I could see what files were being loaded as programs started.

No. Actually.

I still have our 486 "tower-and-a-half." We built it using a case that was at least 30-inches (0.76-m) tall. I'll have to dig it out one day to see if it will still run. I *think* that I still have every computer (except one 386 system) that I ever had, starting with a TRS-80 Model III. All of my following machines ran either MS-DOS or different versions of Windows (3.11, NT, and up until Windows 7). Then came my PDP-8s (which take a *lot* of space, being rack-mounted), and I was given a C-64 by a coworker whose wife decided that he didn't need to keep it anymore. My original 8086 machine (a clone) "works," except that the ~10MB HDD finally died and decided to no longer turn (I suppose the heads stuck to the platter).

As far as I know, it was done by hooking the timer interrupt

@@overbored1337 The timer interrupt hook could be used with any version of DOS by any program, including Desqview to simulate multitasking. If MSDOS 4.00 was called "multitasking" out of the box, it should support simultaneous programs running or have a formal multitasking API.

@@jazzerbyte I always used the timer interrupt because of backwards compability, because even 386 instructions were discouraged in real mode dos programs long into the pentium era.

Here is a question for you. What makes an .exe vs a .com?? And no, I don't mean an internet domain name here. It's an MSDOS question and a very easy one.

@@RCShadow the format itself

@@RCShadow The com is basically just a small exe with the header omitted, replaced with default values, so its basically a raw binary program with defaults like shared code/data/stack segment, no entrypoint & no relocations to name a few

@@RCShadow .exe format starts w/ MZ. Com is older and was inherited from CP/M. IIRC the MZ format / exe's start with MS/PC DOS 2.0

@@RCShadow The ".com" files are up to 64K in size, ".exe" files are anything larger than that, if memory serves.

I saw someone comment that MS have only released source for the versions of DOS that were unsuccessful ;)

Haven't checked the rest of the comments but back in the day we referred to 4.01 as A Mess DOS. Or where the heck did all my low memory go. MSDOS 5 felt like an apology and was the version I rocked right up until Windows 95.

All that and you never learned the important role played by the apostrophe in contractions!

It's a setting in git. I don't think github modified the files. How line breaks are converted when cloning the repo and when committing is configurable in the git config. He cloned the repo to a mac, so he likely had his git configured to convert the line breaks to unix format. When he exposed the file system to dosbox, he had broken line breaks.

@@paulsaulpaul Yep, totally how you configure git. It always stores files as-is, but you can ask it to translate the line endings when you check out the files.

MS-DOS was always open source if you wanted to decompile it back to ASM :P It's not like PCs back then had stuff like TPMs that could be used to encrypt the code on-disk or block access to stop it from just being read plainly and seeing what was going on.

@@wasd____ tbh, not like if i had the brain enough to decompile it as it was... as well, i guess it was worth to have waited for MS to open source it instead of reverse-compiling it :P legal terms...