21–30 of 37 posts
Ah the icon... the one system where you can just tell it to run a shell as root to gain superuser privileges... https://www.juliandunn.net/2006/08/21/on-hacking-the-unisys-...
Each classroom had a IIe, some with green screens and some with colour monitors. All outfitted with a well-rounded collection of educational game 5 1/4” floppies.
We also had a networked Mac Plus computer lab with a couple of Performas at the “head” of the table.
The 186 produced some obscure, kinda great, but ultimately doomed (due to not being PC compatible) systems in the early 80s. My favorites are the Tandy 2000 and the Mindset. This is one I haven't heard of. I'm also fascinated by the early Canadian personal computer scene. They were trying some innovative things in the great white North. Things like the mostly PC compatible Hyperion, which beat the Compaq Portable to…
The Tandy 2000 was the only 80186-based machine I'd known of until now. I actually had one for a while, bought from Radio Shack when they were quietly dumping the remaining stock for something like 90% off. It was like a computer from a slightly alternate timeline, one where MS-DOS's original notion of not being tied to PC-specific hardware (e.g., more like CP/M) actually took off.
In the early 80s, when it wasn't yet clear that PC clones would dominate, it was a wonderful machine: it had a workstation-class (for the time) graphical display and was faster than any IBM product until the second-rev AT came out.
Microsoft was more focused on being cross-platform back then. Multiplan, for instance, ran on an abstract machine and so was ported to everything from minicomputers to the frickin' TI-99/4A. They even tried to consolidate Xenix and MS-DOS on a single unified API called "XeDOS"; fun fact: this is how MS-DOS 2.0 got subdirectories and piping/redirection.
Did you spot the Tandy 2000 used as a prop in Stranger Things? It was the cash register for the video store they used to search for Eddie in I believe Episode 2 of Season 4.
The 186 produced some obscure, kinda great, but ultimately doomed (due to not being PC compatible) systems in the early 80s. My favorites are the Tandy 2000 and the Mindset. This is one I haven't heard of. I'm also fascinated by the early Canadian personal computer scene. They were trying some innovative things in the great white North. Things like the mostly PC compatible Hyperion, which beat the Compaq Portable to…
512K RAM, MMU (discrete logic), 4x serial, 10MB hard disk, floppy. No keyboard or video interface; you were expected to use serial terminals, typically three of them for users, with the fourth port used for a printer. Ran Xenix 1.0 which was basically V7 Unix ported to the platform. No networking except what would run over a serial port.
I got a fully working one at a garage sale for $40 in the early 1990s and geeked out with and learned quite a bit about Unix on it for a while. Since it had about the same limitations as a PDP11 and Minix (64K code, 64K data) there was, in those days, a fair bit of software that could be made to run (i.e. lightly ported) easily. I remember getting a vi clone going that used 63K of the possible 64K code space. V7 didn't have a fullscreen editor stock.
Long gone now. By the time Linux became my main OS a few years later, this was still in the "junk" category rather than "valuable collector's item" category and I gave it away.
The 186 produced some obscure, kinda great, but ultimately doomed (due to not being PC compatible) systems in the early 80s. My favorites are the Tandy 2000 and the Mindset. This is one I haven't heard of. I'm also fascinated by the early Canadian personal computer scene. They were trying some innovative things in the great white North. Things like the mostly PC compatible Hyperion, which beat the Compaq Portable to…
Another pretty obscure Canadian non-PC 8086 or 8186 was the NABU 1600 or 1200 (never did figure out which was the right number). NOT the NABU that ran off the cable network. 512K RAM, MMU (discrete logic), 4x serial, 10MB hard disk, floppy. No keyboard or video interface; you were expected to use serial terminals, typically three of them for users, with the fourth port used for a printer. Ran Xenix 1.0 which was basi…
These systems had numerous problems, one of which was the school board's severe lack of resources to manage them. The teachers were limited in what they were allowed or able to do, so if a lab went down, it typically took about a week to get someone to fix it. As students, we used this to our advantage. I have fond memories of causing all sorts of issues on these systems as a kid. Another perk was that my school wasn’t air-conditioned, except for the computer labs, so during the hot months it's where you wanted to be.
The 186 produced some obscure, kinda great, but ultimately doomed (due to not being PC compatible) systems in the early 80s. My favorites are the Tandy 2000 and the Mindset. This is one I haven't heard of. I'm also fascinated by the early Canadian personal computer scene. They were trying some innovative things in the great white North. Things like the mostly PC compatible Hyperion, which beat the Compaq Portable to…
British schools were filled with these non-IBM compat, DOS compat 80186 PCs: https://en.wikipedia.org/wiki/RM_Nimbus
Ah the icon... the one system where you can just tell it to run a shell as root to gain superuser privileges... https://www.juliandunn.net/2006/08/21/on-hacking-the-unisys-...
It was possible to poke two byte memory locations with the value 255, run a new shell, and you would be root. I figured that out by comparing memory dumps as different users, figuring out which locations corresponded to user and group number.
We figured out how to create a SUID shell, so we could get back to root even after we head logged out. Poking a few bytes would have been more interesting!
Earlier quoted context omitted.
It was possible to poke two byte memory locations with the value 255, run a new shell, and you would be root. I figured that out by comparing memory dumps as different users, figuring out which locations corresponded to user and group number.
At our school, the "computer" teachers were often teachers who were specialists in other areas that had some interest in computers, and weren't very ... security aware. They all had admin/root user access, and they'd often forget to sign out, leaving us with the keys to the kingdom, at least temporarily. We figured out how to create a SUID shell, so we could get back to root even after we head logged out. Poking a fe…