Linked by Thom Holwerda on Mon 5th Feb 2018 23:08 UTC
Windows

In November last year I wrote about the forgotten and obscure feature of early Windows 95 builds that lets you run Windows 3.1 in a window on Windows 95. Since then I was wondering if this would still work on the final build (950) of Windows 95, considering so much has changed since build 58s.

I won't spoil it.

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RE[2]: Reminds me of OS/2 2.0
by Drumhellar on Tue 6th Feb 2018 21:28 UTC in reply to "RE: Reminds me of OS/2 2.0"
Drumhellar
Member since:
2005-07-12

Windows 3.1 was basically a DOS application.


No, it wasn't. It was an actual operating system, really, by any reasonable definition of the word. Basically, everything that an operating system does, Windows 3.1 without using DOS, and handled many things that DOS couldn't.

Sure, it started from DOS, but when you launched Windows, it would replace DOS with a 32-bit hypervisor that would run a virtual machine with a single instance of Windows 3.1, as well as DOS virtual machines for running DOS apps. The Windows 3.1 instance and the DOS virtual machines were pre-emptively multitasked.

As for the Windows 3.1 machine, it provided virtual memory (including paging to disk), its own interrupt handler (and didn't use DOS's), it used its own drivers for disks, mouse, audio, printing, and networking (When available - it could also use DOS drivers if Windows drivers weren't available). The disk driver is especially significant, as it as a 32-bit protected mode driver that completely by passed DOS and BIOS function calls.

Sure, it was closely tied to DOS, but it was definitely an operating system in its own right, and certainly not just "basically a DOS application."

It's really more like... an operating system that runs next to DOS, and sometimes asks DOS for a cup of sugar or whatever.

Reply Parent Score: 7

RE[3]: Reminds me of OS/2 2.0
by ianm on Tue 6th Feb 2018 23:34 in reply to "RE[2]: Reminds me of OS/2 2.0"
ianm Member since:
2010-08-16

Good times!

Your post brought be back to Usenet newsgroup discussions from late 80's through early 90's.

Reply Parent Score: 1

RE[3]: Reminds me of OS/2 2.0
by Andre on Fri 9th Feb 2018 10:25 in reply to "RE[2]: Reminds me of OS/2 2.0"
Andre Member since:
2005-07-06

What makes an operating system an operating system rather then an application, especially in the (MS-)DOS days? Back in the days where each application that handles sounds had to include its own support, rather then rely on the operating systems support.

Stating that Windows 3.1 used its own drivers, well.... running on top of (MS-)DOS you had to for most hardware. Okay, there were DOS drivers for mice, but that's about it. And for CD-ROM drives, Windows 3.1 depended on the support DOS offered.

Reply Parent Score: 1

Drumhellar Member since:
2005-07-12

What makes an operating system an operating system rather then an application, especially in the (MS-)DOS days?


At the most basic, probably the interrupt handler. When an interrupt is generated by a piece of hardware, the OS is what handles it. When a piece of software generates an interrupt, it is to notify the OS that there is work to be done.

When Windows loads, it nukes the DOS interrupt handler and replaces it with its own. Windows (not DOS) handles both hardware and software interrupts. The hardware is interacting with Windows directly, not DOS.

Reply Parent Score: 2