- Welcome to NeXTcommunity.
News:
Stuttgart museum purchases 40 NeXT machines from Rob Blessin
Recent posts
#41
Virtualization / Previous JIT Compiler
Last post by jeffburg - Nov 09, 2025, 02:42 AM@andreas_g I'm assuming there is a reason, but I was wondering why Previous does not include the JIT compiler from Hatari... like maybe it does not work with the other custom chips developed for previous?
https://github.com/hatari/hatari/tree/main/src/cpu/jit
https://github.com/hatari/hatari/tree/main/src/cpu/jit
#42
Virtualization / Re: Previous running on PowerP...
Last post by jeffburg - Nov 09, 2025, 01:46 AM@Rhetorica @ZombiePhysicist Yes, this build already has those cache optimizations enabled. But to your point about running on a toaster... I don't see why it's not possible because the 68040 is just so old and so weak, basically anything should be able to properly emulate it.
And I agree it seems like a strong goal of Previous was to be very accurate, but I wonder how much faster it could go and still work. As someone said elsewhere, NeXTstep is not very timing sensitive.
For comparison, on this same iMac, I installed VirtualPC 7 which emulates Intel 32 bit. I am going to try to install OpenStep on that... but handily the VirtualPC install disc came with an installation of Windows XP. So I booted up Windows XP on this iMac and it runs fine. So I think if a G4 can emulate an Intel processor and run Windows XP at a reasonable speed, it should be able to run an operating system and chip that are literally 10 years older at a much faster speed.
https://www.macintoshrepository.org/759-microsoft-virtual-pc-7-0
And I agree it seems like a strong goal of Previous was to be very accurate, but I wonder how much faster it could go and still work. As someone said elsewhere, NeXTstep is not very timing sensitive.
For comparison, on this same iMac, I installed VirtualPC 7 which emulates Intel 32 bit. I am going to try to install OpenStep on that... but handily the VirtualPC install disc came with an installation of Windows XP. So I booted up Windows XP on this iMac and it runs fine. So I think if a G4 can emulate an Intel processor and run Windows XP at a reasonable speed, it should be able to run an operating system and chip that are literally 10 years older at a much faster speed.
https://www.macintoshrepository.org/759-microsoft-virtual-pc-7-0
#43
Virtualization / Re: Previous running on PowerP...
Last post by jeffburg - Nov 09, 2025, 01:41 AM@andreas_g When I ran sudo make install it looks like it relinks the binary and packages the dependencies right in the bundle... is that the case? If so I will zip it up and upload it here if anyone is curious.
#44
Virtualization / Re: Previous running on PowerP...
Last post by ZombiePhysicist - Nov 08, 2025, 06:52 PMWow super cool. We are now one step closer to Previous running on toasters! 
#45
Virtualization / Re: Previous running on PowerP...
Last post by andreas_g - Nov 08, 2025, 06:04 PMFantastic work! Well, the performance does not surprise me. I started development of Previous on an iMac G5 and that was also hardly usable. Anyway a great proof of concept!
This could be used for debugging endianness issues. Maybe some C developer with an old PPC Mac picks up your builds and does the porting required (definitely for the ND emulation and maybe some bugs in the networking part).
This could be used for debugging endianness issues. Maybe some C developer with an old PPC Mac picks up your builds and does the porting required (definitely for the ND emulation and maybe some bugs in the networking part).
#46
Virtualization / Re: Previous running on PowerP...
Last post by Rhetorica - Nov 08, 2025, 04:57 PMWow, nice work! Did you try messing with the performance-boosting settings we were discussing recently? Less accurate emulation might be the key here...
#47
Virtualization / Re: Previous running on PowerP...
Last post by jeffburg - Nov 08, 2025, 04:06 PM@marvin haha thanks. I live in Japan, so of course the dorky cute mouse is the cheapest thing available. But it also fits the theme of the computer. In Japan they call these iMacs "Daifuku" Macs because they look like the dessert. So I found some cute Daifuku pictures and made it into a little theme.
https://www.yodobashi.com/product-detail/100000001003173439/
https://www.yodobashi.com/product-detail/100000001003173439/
#48
Virtualization / Re: Previous running on PowerP...
Last post by marvin - Nov 08, 2025, 03:41 PMThis is really great, thanks for sharing!
From the running speed it reminds me on my experiments with UAE running Amiga games on a 25 MHz NeXTstation. It kind of worked, but performance was not so good
EDIT: and I really like your cute mouse with the nice face!
From the running speed it reminds me on my experiments with UAE running Amiga games on a 25 MHz NeXTstation. It kind of worked, but performance was not so good
EDIT: and I really like your cute mouse with the nice face!
#49
Virtualization / Previous running on PowerPC Ma...
Last post by jeffburg - Nov 08, 2025, 03:18 PMHey Folks,
Previous has an official minimum deployment target of Mac OS X 10.13. Considering its release year of 2017, that seems like quite a long run of support. However, now that I got my iMac G4, I wondered if it could be run on older systems...
How about Mac OS X 10.5 Leopard from 2007?
I am happy to say that I spent an absurd amount of time to do something totally pointless. I back-ported both SDL 2.26.x and Previous to Leopard, although SDL was quite a bit more difficult as Previous needed almost no changes. I've never done anything like this before but it was kind of fun to do the back-porting 100% with GCC, GDB, and the command line.
Right now the SDL code is quite rough because I just wanted to see if it would work at all. I do want to spend some time cleaning up SDL because it's probably leaking memory and has hidden crashers, however I have spent an unexpectedly large amount of time on this and I am kind of burned out on it, so it might take a bit of time for me to pick it back up again.
Also, the performance is worse than I expected... When I run a 68030 machine at 25MHz, it says it's running at about 30% of full performance. Also, networking seems to not be working. Anyway, I consider this to be a sort of POC... but hopefully in the future, people will be able to take advantage of SDL 2.26.x for PPC. The latest one I found online was 2.0.6 and that was too old for Previous (and probably many other apps).
I attached photos as well as build logs for SDL and Previous. You can see the pull requests with the links below.
See Patch/Changes for Previous
See Patch/Changes for SDL2
Previous has an official minimum deployment target of Mac OS X 10.13. Considering its release year of 2017, that seems like quite a long run of support. However, now that I got my iMac G4, I wondered if it could be run on older systems...
How about Mac OS X 10.5 Leopard from 2007?
I am happy to say that I spent an absurd amount of time to do something totally pointless. I back-ported both SDL 2.26.x and Previous to Leopard, although SDL was quite a bit more difficult as Previous needed almost no changes. I've never done anything like this before but it was kind of fun to do the back-porting 100% with GCC, GDB, and the command line.
Right now the SDL code is quite rough because I just wanted to see if it would work at all. I do want to spend some time cleaning up SDL because it's probably leaking memory and has hidden crashers, however I have spent an unexpectedly large amount of time on this and I am kind of burned out on it, so it might take a bit of time for me to pick it back up again.
Also, the performance is worse than I expected... When I run a 68030 machine at 25MHz, it says it's running at about 30% of full performance. Also, networking seems to not be working. Anyway, I consider this to be a sort of POC... but hopefully in the future, people will be able to take advantage of SDL 2.26.x for PPC. The latest one I found online was 2.0.6 and that was too old for Previous (and probably many other apps).
I attached photos as well as build logs for SDL and Previous. You can see the pull requests with the links below.
See Patch/Changes for Previous
See Patch/Changes for SDL2
#50
Hardware / Re: NeXTDimension VRAM error
Last post by andreas_g - Nov 08, 2025, 01:03 PMLooks very strange. I can't see a pattern either. Maybe some hardware experts are around who have an idea what might cause this kind of errors.