operating system

20 Articles

MULTICS Gets A New Release… 52 Years After Launch

August 7, 2021 by 27 Comments

If you have ever read anything about the history of UNIX, you may remember that its early development was influenced by an older operating system. MULTICS was developed in the 1960s by MIT and General Electric as a commercial operating system, and had been the system which UNIX writers [Thompson] and [Ritchie] had used. It became a Honeywell product, and the source code for its final commercial version was eventually released to the public. Has it become a dusty relic of interest only to historians? Seemingly not, because a new version has been released. It’s intended for us on the dps8m Honeywell mainframe simulator rather than physical hardware, so perhaps while it’s not such a dusty relic it remains something only for the enthusiast.

We won’t pretend to be experts on the architectures of 1960s mainframe operating systems, but it’s interesting to read for a moment about what it was in MULTICS that caused UNIX to be written. For something described by [Ken Thompson] as “Close to unusable”, with a fresh release in its 52nd year it isn’t doing badly.

We’ve traced the UNIX story in the past, without realising that MULTICS never entirely went away. Shame on us for the omission!

[Via Hacker News]

Tiny Operating System For Tiny Computer

June 28, 2021 by 12 Comments

Before the World Wide Web became ubiquitous as the de facto way to access electronic information, there were many other ways of retrieving information online. One of the most successful of these was Minitel, a French videotex service that lasted from 1980 all the way until 2012. But just because the service has been deactivated doesn’t mean its hardware can’t be used for modern builds like this Arduino-based operating system. (Google Translate from French)

Called ZARDOS, the operating system is built to run on an Arduino MEGA although a smaller version is available for the Uno. The Arduino is connected by a serial cable to the Minitel terminal. It can take input from a keyboard and PS/2 mouse and displays video on the terminal screen with the same cable. There is functionality built-in for accessing data on a cartridge system based on SD cards which greatly expands the limited capabilities of the Atmel chip as well, and there is also support for a speaker and a Videotex printer.

Even though the build uses a modern microcontroller, it gives us flashbacks to pre-WWW days with its retro terminal. All of the code is available on the project site for anyone looking to build an Arduino-based operating system, although it will take a little bit of hardware hacking to build a Minitel terminal like this. Either way, it’s a great way to revive some antique French hardware similar to a build we’ve seen which converts one into a Linux terminal.

Thanks to [troisieme_type] for the tip!

Reaching Serenity: Porting Git To A Homebrew Operating System

February 23, 2020 by 6 Comments

Life is all about the little joys — such as waking up in the morning and realizing there’s still plenty of time before you have to actually get up. Or getting up anyway to watch a delightful sunrise as the city slowly wakes up, or as [Andreas Kling] chose, porting your favorite development tool to the operating system you wrote.

With the aesthetics of ’90s UI design and the functionality of a simpler 2000s Unix-style system core in mind, and personal reasons to keep himself busy, [Andreas] started SerenityOS a little while back. Of course, writing your own operating system is always a great educational exercise, but it takes a certain amount of commitment to push it beyond an experimental playground phase. So ideally, you’d eventually want to use it as your actual main system, however, as software developer, [Andreas] was missing one crucial component for that: git. Well, he decided to change that and just port it — and as someone who likes to record his hacking sessions, you can watch him along the way.

Admittedly, watching someone tweaking some build tools and compiler settings would normally sound anything but overly exciting, but it adds a few more layers to it when doing so for a work-in-progress OS written from scratch — from digging into libc implementations to an almost reverse engineering approach to the build environment. If you take pleasure in people’s thought process in problem solving and (spoiler alert) their success, you will enjoy watching [Andreas]. On the other hand, if you’re more curious about a fresh approach at a desktop operating system, SerenityOS itself might be worth looking into. Of course, there are other options for that as well.

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Pack Your Bags – Systemd Is Taking You To A New Home

October 16, 2019 by 175 Comments

Home directories have been a fundamental part on any Unixy system since day one. They’re such a basic element, we usually don’t give them much thought. And why would we? From a low level point of view, whatever location $HOME is pointing to, is a directory just like any other of the countless ones you will find on the system — apart from maybe being located on its own disk partition. Home directories are so unspectacular in their nature, it wouldn’t usually cross anyone’s mind to even consider to change anything about them. And then there’s Lennart Poettering.

In case you’re not familiar with the name, he is the main developer behind the systemd init system, which has nowadays been adopted by the majority of Linux distributions as replacement for its oldschool, Unix-style init-system predecessors, essentially changing everything we knew about the system boot process. Not only did this change personally insult every single Perl-loving, Ken-Thompson-action-figure-owning grey beard, it engendered contempt towards systemd and Lennart himself that approaches Nickelback level. At this point, it probably doesn’t matter anymore what he does next, haters gonna hate. So who better than him to disrupt everything we know about home directories? Where you _live_?

Although, home directories are just one part of the equation that his latest creation — the systemd-homed project — is going to make people hate him even more tackle. The big picture is really more about the whole concept of user management as we know it, which sounds bold and scary, but which in its current state is also a lot more flawed than we might realize. So let’s have a look at what it’s all about, the motivation behind homed, the problems it’s going to both solve and raise, and how it’s maybe time to leave some outdated philosophies behind us.

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Bringing PalmOS Back To Life

May 21, 2019 by 28 Comments

Ten years is almost ancient history in the computing world. Going back twelve years is almost unheard of, but that’s about the time that Palm released the last version of their famed PalmOS, an operating system for small, handheld devices that predated Apple’s first smartphone by yet another ten years. As with all pieces of good software there remain devotees, but with something that hasn’t been updated in a decade there’s a lot of work to be done. [Dmitry.GR] set about doing that work, and making a workable Palm device for the modern times.

He goes into incredible detail on this build, but there are some broad takeaways from the project. First, Palm never really released all of the tools that developers would need to build software easily, including documentation of the API system. Since a new device is being constructed, a lot of this needs to be sorted out. Even a kernel was built from scratch for this project, since using a prebuilt one such as Linux was not possible. There were many other pieces of software needed in order to get a working operating system together running on an ARM processor, which he calls rePalm.

There are many other facets of this project that we aren’t able to get into in this limited space, but if you’re at all interested in operating systems or if you fondly remember the pre-smartphone era devices such the various Palm PDAs that were available in the late ’90s and early ’00s, it’s worth taking a look at this one. And if you’d like to see [Dmitry.GR]’s expertise with ARM, he is well-versed.

Thanks to [furre] for the tip!

Grabbing The Thread: Spinlocks Vs Mutexes

March 24, 2019 by 31 Comments

Getting into the weeds of operating systems is daunting work. Especially when the operating system involved is a fully featured modern PC operating system with millions of lines of code all working together to integrate hardware and software seamlessly. One such operating system “weed” is figuring out how to handle simultaneous tasks when the processor can only really handle one thing at time. For that, you’ll be looking at the difference between spinlocks and mutexes.

Both of these are methods of making sure that the processor completes a task sufficiently before moving on to the next task. Modern computers are so fast (even ignoring multiple cores) that it seems as if they are doing many things at once. In order to maintain this illusion, tasks need ways of locking the processor to that specific task for a certain amount of time. Of course the queue for performing the next task can get complicated as there are often many tasks waiting to use processor time. Spinlocks are a simple way of holding the processor and mutexes are a slightly more complicated way, but which one is the most efficient use of system resources isn’t that straightforward.

If you’ve ever been interested in operating system details, this one goes deep into the intricacies of features most of us have never even considered the existence of. It’s definitely worth a read, though, and is very well written by someone who is clearly an expert. If you want an operating system challenge, you can build your own operating system as well.

Pocket Forth Invades Your TI Calculator

January 25, 2019 by 7 Comments

TI certainly have certainly seen off rivals such as HP or Casio to capture the lion’s share of the calculator market. The TI-84 is a real staple, and with as many units as there are out there, hacking them is a given. However, selecting an operating system for the machine can be a hassle. TI-OS is proprietary and doesn’t really want to let you do everything you’d like to. There are alternatives, but many of them won’t let you easily use your calculator to be — well — a calculator.

[Siraben] has zkeme80 which is essentially ANS Forth (mostly) with extensions for the TI hardware. You can easily extend the system, of course, because it is Forth. You can also use the machine for its intended purpose easily.

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