70

You are comparing apples to motorcycles. Windows 95 traces its lineage back through Windows 3.x all the way to Windows 1.x and MS-DOS/PC-DOS, themselves inspired by CP/M. It was conceived and designed as a single-user, cooperatively multitasking environment in which applications have a large degree of freedom in what to do. Windows 95 moved towards a ...


37

The decision about whether to kill a process or crash the OS generally depends on whether the problem can be isolated to the process. For example, if a running process in user mode attempts to read from an address that's not present in its address space, that's not going to affect anything else. The process can be terminated cleanly. At the other extreme, ...


33

The simple answer is that early operating systems for the systems you mention did not provide those features. Apple DOS, for example, makes no use of interrupts, and has no concept of processes or memory protection. Nor does DOS have any concept of hardware drivers, as it includes support to drive the Disk II (a deep assumption in DOS) and nothing else. ...


25

For "home" computer systems such as the Apple II, the "operating system" wasn't anything like a modern one with processes and device drivers and so on; by the standards of modern OSes there wasn't really one at all. As a warning: all these explanations (long as they are) are for the most part considerably simplified. This answer is intended to give you the ...


23

I have not found a reference, but here's a search for OS/2 on Trend Micro's virus encyclopedia. That finds 30 entries, some of which are actual OS/2 viruses, and some of which are interesting OS/2 security vulnerabilities. It looks as if there are five OS/2 viruses in that list, but it's unknown if any of them are multiple names for the same virus, or ...


23

TL;DR: on 286s in standard-mode Windows, DOS programs run one at a time in real mode, with Windows suspended, so the restrictions of enhanced mode which rendered DPMI necessary don’t apply. The “trick” used to allow unmodified Windows 2 programs to run in protected mode on a 286 relies largely on the fact that Windows provides a full operating system API to ...


22

In order to load files from the SYS volume NetWare needs to have a device driver for the kind of disk your SYS volume lives on. Considering that you might put your SYS volume on an MFM drive, or RLL, or ESDI, or SCSI, or IDE, or any of a variety of different RAID controllers, we are talking about a lot of different devices your bootloader needs to be able ...


21

The cited source from the question is the source for the English Wikipedia page as well, that claims that there are only very few known viruses for that system. But the low amount of viruses seems to be much bigger. Not two, but at least five viruses are well known. That's more than double. Arelocs also known as Aep is one of a few viruses for IBM's OS/2 ...


20

The technical differences are large when compared to the technical similarities. CTSS was built for a modified IBM 7094 system while ITS was built for the DEC PDP-6 (later PDP-10). Both of these machines were organized around 36 bit words, but the similarity tails off after that. Both machines lacked a hardware page map, and did not attempt to provide ...


17

OS/2 supported “huge memory” on 286s. The New Executable format used for 16-bit OS/2 executables (and 16-bit Windows executables) supports multiple segments. At runtime, using the DosAllocHuge function, programs could allocate more than 64KiB of memory at a time, and would get a sequence of segment selectors which could be used to easily access all the ...


17

Most early microcomputer operating systems were single-level - Apple DOS, CP/M, MS-DOS/PC-DOS prior to version 2.0, UCSD P-System, whatever Commodore called their DOS for the PET/CBM and C64. With the exception of UCSD P-System, which had a maximum of 77 files in the directory, I don't believe any of them had an inherent limit to the number of files, but ...


17

The whole CP/M family of operating systems, until Concurrent DOS, had both a limited number of files per drive and no hierarchy except for user areas. From the Wikipedia article: CP/M 2.2 had no subdirectories in the file structure, but provided 16 numbered user areas to organize files on a disk. To change user one had to simply type "User X" at the ...


17

We talk about the late 1970s and mainstream 6502 machines, right? It wasn't so much that programs run under OS control as that OS was a support function to Programs. More like what we would today see as a standard library with routines supporting simple I/O abstraction plus basic file handling on the user side and hard coded drivers within. Some, like ...


12

The typical circa-1980 8-bit CPU provided almost no support for modern operating system features. It was often possible to add such support using external logic, but very few machines actually did so because it would have added costs to the hardware with little practical benefit. Even many minicomputers of the time left those features out, at least in the ...


11

From the perspective of today and looking backwards to the use of language in this commercial we apply different semantics than would have been perceived at the time. The same is true when interpreting anything historical - we just don't expect it to apply to something (relatively) so modern and contemporary. I was, at the time of this commercial, ...


11

Although Windows 95 introduced support for 32 bit applications with memory protection, it was still somewhat reliant on MS DOS. For example, where native 32 bit drivers were not available, it used 16 bit DOS drivers instead. Even 32 bit applications had to be synchronized with the 16 bit DOS environment. A fault in the DOS part of the system would bring the ...


10

The Classic AmigaOS had a very good reason for not implementing protected memory when newer 68k CPUs with embedded MMUs became commonplace. The main reason was the pervasive use of shared memory message passing to communicate between tasks, including user tasks, system tasks, and device drivers. The main reason that AmigaOS out-performed all other ...


10

Yes. Several. Consider, for example Dec RSTS/E. This was a flat directory structure. Now, to be clear, the system had separate accounts. So, each user would have their own account/directory. Very similar to Users in CP/M. But they weren't hierarchical. As for RSTS/E file capacity, I don't know the specifics, but I'm sure it had a limit of the total number ...


10

In addition to the examples already given a couple more used a flat data structure with an absolute limit on the number of files but one property assigned to each file was its directory. So the real storage was single level — a single data structure, with file names being required to be unique across the entire disk — but it was presented as if a single ...


10

Contemporary operating systems for the 6502 did not have those features. But not because they couldn't. It just wasn't considered necessary or desirable. Provide automatic switching between processes. The standard trick here is to have a clock attached to an interrupt that the OS can use to perform a context switch. This seems doable on the 6502 with ...


9

The answer is simple, Jobs was simplifying for the media.


8

What, this documentation? I found this by searching for Eyring on the Internet Archive, finding Eyring.com, going to their earliest 2002 snapshot and clicking on the EYRX link. Unfortunately, the operating system itself was hosted on an FTP server, and those aren't archived by the Internet Archive. So we'll see if somebody else can find it.


8

From Network World: NetWare never ran on top of DOS. A server was booted to DOS solely to run the NetWare boot loader (a DOS program). It didn't need to do that, it could have booted directly but that would have required Novell to build its own BIOS loader to initialize all of the hardware. The NetWare designers felt that there was no need to ...


7

Some old Operating Systems I hear have only BASIC Programming Language It was more the case that BASIC was the operating system. Various commands for working with devices like floppy disks and printers were added to the dialect of BASIC running on that machine. Turning it on would result in the BASIC READY prompt where you could type in a program, or begin ...


7

The closest I've ever seen was the Enforcer tool which would utilize the MMU on systems with one to protect against illegal memory accesses. It was good to have it running while you were debugging code, but otherwise was pointless to run in normal operation. I imagine there was never a serious push to implement memory protection simply because I believe ...


7

Does 'single level' mean exactly one directory a la early DOS floppies, i.e., no directories other than the root? Or does it mean multiple directories, no nesting, except maybe of user directories in the root directory? So you have directories /foo and /bar, and we can overlook the fact that there's actually a directory called / which contains foo and ...


7

ToolShed seems to be the current maintained OS9/descendants disk manager tool. It's not a file browser but works on the command line. Are you sure your disk image is a valid RBF image, though? Toolshed refuses to read it: $ os9 dir os9000-xibase.img dir: error 216 opening 'os9000-xibase.img,' dir: error 216 opening 'os9000-xibase.img' Similarly, checking ...


6

RISC OS Pico on the Raspberry Pi boots to BASIC. See https://www.riscosopen.org/content/downloads/raspberry-pi The "full fat" RISC OS could also be made to boot to BASIC using *CONFIGURE commands like you can with the Archimedes and RISC PC. Note that riscosopen.org do not list the RasPi4 as being compatible (and RISC OS Pico has a smaller compatibility ...


6

The previous answer talks about various issues that may arise when attempting to run an older OS on a modern system, but doesn’t really focus on the questions asked. When a multicore CPU powers on, a single core is activated. The BIOS typically has a configuration option to control how many additional cores should be activated. If this BIOS setting is set ...


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