The Original CP/M: A Look Back at the Classic Operating System

We're looking at a year's worth of NIT-based code blue computer kit, and what we have here is actually an original CP/M system written for the 8080. The 80s is an extension of the 8080, so it runs all of the 8080 code. This means that we're running one of the original versions of CP/M exactly as it would have done back in the day.

The CP/M system includes a small little bootloader and allows us to select to boot into CP/M. The specific BIOS for this is written by a guy called Grant Searle, who needed to face the challenge of creating code for generic hardware. Fantastic work there! However, once we get past the BIOS, we're back to what a lot of people know as a familiar command prompt - we're at the I I disk command prompt.

One of the fantastic things about CP/M is that it was incredibly popular and had a wealth of software available. There were business software applications like WordStar, which was the first real word processor, and database programs like DBase. If you were a business user, using CP/M could be an attractive option because you didn't have to do your accounting on it and other tasks. There were also games and utilities available for CP/M.

However, what really set CP/M apart was its ease of use. Because the system included tools for writing assembly code, users could create their own programs with relative ease. The assembler, in particular, was a powerful tool that allowed users to create executable code from source. This made it easy to write and customize software, which contributed to the system's popularity.

One of the most iconic applications for CP/M is the classic adventure game Zork. Running Zork on a PDP-11 just a few weeks ago brought back memories of playing the game as a kid. The gameplay was incredibly addictive, and it's still remembered fondly by many today. There were also other space-themed adventure games available for CP/M that were equally enjoyable.

In addition to its applications, CP/M also had a number of limitations. It didn't care about graphics at all - it only sent out serial data. This meant that users needed a suitable graphics card and BIOS in order to run certain programs or play games. However, with the right hardware setup, CP/M could do some amazing things.

The RC 2014 comes as an example of how well CP/M can work with certain hardware configurations. By using a graphics card and tweaking the BIOS settings, it's possible to get a decent display out of the system. This is demonstrated by running a simple game that uses ASCII characters to create a familiar layout.

Another notable machine that runs CP/M is the Illustrated PCW 1512. This was one of the biggest selling machines in the UK market and was bundled with CP/M from the factory. The BIOS was custom-written to work seamlessly with the hardware, and once booted up, it ran like standard CP/M.

The rest of the system includes a few basic CP/M commands that demonstrate how user-friendly the interface is. Once you get past the boot-up process, things become familiar - the syntax looks almost identical to DOS or Linux. This is due in part to the popularity and influence of CP/M on later operating systems like MS-DOS.

In fact, it's widely acknowledged that Microsoft took a lot from CP/M when developing MS-DOS. The learning curve for getting up to speed with MS-DOS was smaller than with completely different operating systems, thanks in large part to the familiarity provided by CP/M. Sometimes, floppy disks would die or become obsolete, but backup copies were always made - a testament to the importance of data preservation.

Finally, there's the game Lander, which became a full-fledged game due to its popularity.

"WEBVTTKind: captionsLanguage: enWhat we're looking at here is actually a year's NIT based code blue computer kit original CP/M was written for the 8080The said 80s is an extension of the 8080. So it runs all of the 8080 codeSo this is actually running one of the original versions of CP/M exactly as it would have done back in the day, right? SoInitially, there's a small little little bootloader and we select to boot into CP/MThis is now money lead CP/M the specific BIOS for this is written by a guy called grants earnedHe done need to face it forthis this generic hardware stuff, sofantastic work there, but then the B dose and theThe CCP is all original CP/M stuff that's sliding in thereSo we are back to what a lot of people YC is a familiar command promptWe're at the I I disk command promptSo we can pick up a directoryWhat are the fantastic things about CP/M was there was such a wealth of softwareThere was business software things like WordStar was the first real word processor. That was the killer app for itThere was debase the database programso if you if you if he was a business, that's a great reason to use CP/M because you don't actually do yourAccounts on it and all stuff like thatThere was also games all sorts of utilities and stuff like thatBut it was also fairly easy to fight to write your own programs as long as you know a bit upset IT assembly codeCP/M includes the tools to actually writeyour assemblyProgram compile it turn it into an executableand they just bud there as your and whatever you need that program to do well, so it's you would use to write yourassembly code these et is the assembler and that that will actually create yourprogram from your source code that you voted Edie EdieEDD sorry, I'm gonna get so so many comments about that Auto so it's all kidsof course a classic adventure game regular viewsWe run Zork or a version of Zork on the pdp-11 a few weeks. YesI've followed her to 12. Y/o, I've got I've got furthered of what he didBut it all honesty you but I was played about with it firstFirst of all try to find my way around the the big white house and coming across monsters and stuffI didn't get that much further, but it is exactly the same programming ones on CP/M. There's there's a whole wealth ofofTech space adventure games for CP/M which are yeah, which were all fantastic if you like that that kind of thing. There are CP/Memulators online orYou could be could download and actually run CP/M on your machine. So although originally CP/M was written for the 8080Subsequently, that means it. Well. It runs on these NIT. It was also later on ported over to theThe68000it also runs on the8086 I ad send pc infrastructure as well as one or two other thingsI think there's said 8000 and the couple other things as wellSo yeah, there wereQuite a few other Dodds nit machines eventually the read CP/M. CP/M doesn't know or care about graphicsIt knows at least to send out something the way I've got this set up at the momentThis is just a serial terminal. So all this does is send out serial dataBut yeah with a suitable graphics card of the suitable BIOS it will do pretty good graphicsas you'll see from this that'sAbsolutely horribleIt's ended out all of the PT 100 control codes for the game there a lot being interpreted properly byMy avoid requires a graphics cardOkay, so you've got a different way of looking at it out of the RC 2014 comes the war s key dataWhich I've put into a total web you later on a UNIX machineSo it's it's displayed exactly what it should be displayed as opposed to what the quality PI's displayedSo got ourselves a little game here if I play one player gamelet's see how we do all this all the little C characters that's worried aboutIt so it was like a familiar layout to meI'm sure they didn't steal this idea for any any arcade machinesGo grab a power pill would go to eat some monstersAll the fun of joys of Earth ASCII archives grapeYahooSo what we got here then this is one of the biggest selling machines that read CP/M. It's the the Illustrated PCW 1512Yeah, very popular in the UK market. I don't know that he done so great outside of the UKIt was sold effectively as a word processor, but it said IP base they bundled it withCP/M so obviously the guys are edge to edge vote the BIOS to talk to their their hardware side of thingsThe rest of it is standard CP/M as its booted up one of the things you can see thereIt's running a few very basic CP/M commands. So it's setting the default directory. It's copied over pipit's copied over set and it's copied over stuff via the shadows is effectively the same kind of thing because youautoexec.bat and stuff like that thatpeople for me at least MSDOS rolled will will be familiar withsoOnce that's all booted upyou can then doSimilar things like get a directory listing see what's odd. Their syntax looks familiar. Actually, doesn't it?I mean for those of us used to dos yes. Yeah, the syntax is very very familiarIt's it's it's almost a combination of DOS and a little bit of Linux in there as wellI'm sure there's be inspiration these be both both directionsThey are because of the way that CPM work to the fact that it was so popularThat's why Microsoft ms-dos was a cloud to look just like itIt's a bunch of smaller learning curve to go up to ms-dos than what it is to something completely differentSo, sometimes he floppies wood dies he often would make backup copiesLet's try this oneSounds more hopeful and so there was this game called Lander which became the full game's arch\n"