Oh, this was very well timed, thank you. Not because I'm installing Windows 98 (over my dead body) but because I'm trying to get a little operating system I wrote in the early 90's to work in Qemu or VirtualBox. And the article contained a nice hint about the emulation hardware.
It is interesting how what worked flawlessly on the hardware of the time is almost impossible to get to work on these emulators, the fidelity is quite low. But bit by bit I'm making progress in figuring out where the differences are and how to work around them. I've got a basic self-hosted development system working now with all of the data in a ram disk. The floppy, keyboard and VGA screen all work, now I need to figure out why the harddrive controller keeps disappearing.
Oh well, the night is young ;)
Thank you for posting this! It really moved the needle in what already was a super long debug session.
It's true that qemu doesn't aim for fidelity. (Despite the name, qemu isn't exactly an emulator!) The development efforts upstream are almost all about getting modern OSes to work well, and quite often the OS is aware that it's running on qemu and adjusts itself - most notably with the installation of virtio drivers, but also in smaller ways. The Linux kernel has over 1000 references to QEMU in its source code.
Also if you look at qemu's device emulation, that's usually "done" when it can run modern operating systems. Qemu doesn't try hard to emulate the entire IDE or SCSI command set in every detail, or every aspect of old hardware.
Another thing is that qemu is not cycle-accurate at all. Instruction and device timings will be wildly different from real hardware, especially if using TCG.
One really big advantage of DOSBox is that it has Ad Lib emulation. DOSBox is kinda weird and broken when it comes to trying to run Win9x though. It's good when it works at least.
It won't be a great experience, but for MIDI, wouldn't Microsoft GS Wavetable Synth suffice? Doesn't that come with Windows 98? If it's trying to use the nonexistent Ad Lib support, you can probably tell it to use GS Wavetable Synth instead in the MIDI settings?
Context: Win98 doesn't do anything with CPUs that support the HLT instruction, so even when the emulated cpu could be idle it's using 100% of your cpu.
This is a nice clarification story why there was no HLT in the idle loop of Win95/98, but it doesn't really explain why there wasn't an option to enable HTL as an advanced feature by modifying the registry. This is especially true if the HTL-related freezes were mostly a laptop problem. There were many strange options to customize Win9X by altering values in the registry, but not this one.
...and when you install Rain (or similar tools like Waterfall or CPUIdle) on Windows 95/98, counterintuitively, the Task Manager will show permanent 100% CPU usage, even though the CPU is actually idling and running cooler.
For me, the fact that Windows 95/98 can't use the HLT instruction is a reason why I wouldn't use these legacy operating systems to run older software. Not that many programs ran on Win95/98 but not on Win2000. Perhaps except for DOS games, which are better served by DOSBox.
How does Windows 98 work with the fingertouch interface of the iPad? There were some very expensive touchscreen Windows tablets back in the late 90s but they all used a stylus and generally the responsiveness was very slow
In one video I've seen UTM used mouse emulation without absolute positioning: it treated the screen surface as a giant trackpoint nub and you could move away from the current location with variable speed. A native on-screen keyboard is also available.
Why would it handle any differently than a trackpad?
Most non-multitouch touchscreen devices emulate a mouse if there is not a more specific driver available. Trackpads were widely available on laptops at the time and you could jump to any point on the screen with those.
You can click but don't expect any gestures to work.
Oh, this was very well timed, thank you. Not because I'm installing Windows 98 (over my dead body) but because I'm trying to get a little operating system I wrote in the early 90's to work in Qemu or VirtualBox. And the article contained a nice hint about the emulation hardware.
It is interesting how what worked flawlessly on the hardware of the time is almost impossible to get to work on these emulators, the fidelity is quite low. But bit by bit I'm making progress in figuring out where the differences are and how to work around them. I've got a basic self-hosted development system working now with all of the data in a ram disk. The floppy, keyboard and VGA screen all work, now I need to figure out why the harddrive controller keeps disappearing.
Oh well, the night is young ;)
Thank you for posting this! It really moved the needle in what already was a super long debug session.
If you need to emulate (and not virtualize) have a try at pcem.
It's a marvelous piece of engineering which is slower than others, but that's the price to pay for accuracy.
It's true that qemu doesn't aim for fidelity. (Despite the name, qemu isn't exactly an emulator!) The development efforts upstream are almost all about getting modern OSes to work well, and quite often the OS is aware that it's running on qemu and adjusts itself - most notably with the installation of virtio drivers, but also in smaller ways. The Linux kernel has over 1000 references to QEMU in its source code.
Also if you look at qemu's device emulation, that's usually "done" when it can run modern operating systems. Qemu doesn't try hard to emulate the entire IDE or SCSI command set in every detail, or every aspect of old hardware.
Another thing is that qemu is not cycle-accurate at all. Instruction and device timings will be wildly different from real hardware, especially if using TCG.
There is a superior emulator: x86box
If you want to try Windows 95 in UTM, I've done it for you.
https://archive.org/details/windows-95-for-utm
If you don’t need to run on iPad, Windows 98 works great on DOSBox, including audio and CD.
iDOS3 is a great DOSBox iPad app. Not sure if it’s available in the US due to all of the Apple shenanigans.
One really big advantage of DOSBox is that it has Ad Lib emulation. DOSBox is kinda weird and broken when it comes to trying to run Win9x though. It's good when it works at least.
It won't be a great experience, but for MIDI, wouldn't Microsoft GS Wavetable Synth suffice? Doesn't that come with Windows 98? If it's trying to use the nonexistent Ad Lib support, you can probably tell it to use GS Wavetable Synth instead in the MIDI settings?
The problem would be games/software that moves to DOS mode and tries to use SB16 MIDI then
Install Rain 2.0 too, or a similar libre licensed tool.
Context: Win98 doesn't do anything with CPUs that support the HLT instruction, so even when the emulated cpu could be idle it's using 100% of your cpu.
And the story of why HLT was backed out :) Microsoft had no trouble adding it -- even in Windows 95, but... https://devblogs.microsoft.com/oldnewthing/20030828-00/?p=42...
This is a nice clarification story why there was no HLT in the idle loop of Win95/98, but it doesn't really explain why there wasn't an option to enable HTL as an advanced feature by modifying the registry. This is especially true if the HTL-related freezes were mostly a laptop problem. There were many strange options to customize Win9X by altering values in the registry, but not this one.
...and when you install Rain (or similar tools like Waterfall or CPUIdle) on Windows 95/98, counterintuitively, the Task Manager will show permanent 100% CPU usage, even though the CPU is actually idling and running cooler.
For me, the fact that Windows 95/98 can't use the HLT instruction is a reason why I wouldn't use these legacy operating systems to run older software. Not that many programs ran on Win95/98 but not on Win2000. Perhaps except for DOS games, which are better served by DOSBox.
How does Windows 98 work with the fingertouch interface of the iPad? There were some very expensive touchscreen Windows tablets back in the late 90s but they all used a stylus and generally the responsiveness was very slow
In one video I've seen UTM used mouse emulation without absolute positioning: it treated the screen surface as a giant trackpoint nub and you could move away from the current location with variable speed. A native on-screen keyboard is also available.
For absolute positioning a USB input device is emulated, so this might not work in Windows 98 without a suitable driver: https://docs.getutm.app/preferences/ios/#cursor
Why would it handle any differently than a trackpad?
Most non-multitouch touchscreen devices emulate a mouse if there is not a more specific driver available. Trackpads were widely available on laptops at the time and you could jump to any point on the screen with those.
You can click but don't expect any gestures to work.
I liked win 98 back in time I will try to install this on an old pc I have