About multitasking, what's best : AmigaOS, Linux, or Winblows XP ?

[Piru]

1. Linux

New 2.6 kernels have nice nice O(1) scheduler and kernel pre-emption.

2. Mac OS X

BSD scheduler basically, tried and tested solution.

3. Windows

I have no firm details how windows scheduler works, but I believe it's BSD variant, or at least acts very close to it. Whether other parts of the OS are very efficient is separate issue (for example Windows memory paging is quite horrible, well... memory is ultracheap these days :-)). In general, Windows scheduler works fine.

4. AmigaOS

Very limited and aged round robin scheduler. Only pre-Windows 95 and classic Mac OS are worse. Tasks running at higher pririty hog all CPU time from lower pri tasks. Task running at same priority don't have fair CPU time sharing. Executive helps a bit by giving BSDish features. AmigaOS and typical applications are very light, which makes the system very responsive. On the other hand there is single global memory map, no resource tracking, memory protection or swap, making the system faster but more vulnerable and prone to crashes.

PS. I am talking about technical merits and qualities here.

[Piru]

@Speelgoedmannetje
That's more due to ISA legacy HW, rather than windows. Playing with floppies is equally painful under linux IMO... ;-)

[Piru]

@Speelgoedmannetje

SCSI because it was better usable for multitasking purposes (or so I read somewhere).

At that point of history IDE HDDs and controllers were all PIO, that is polled by the CPU. Reading or writing something required full CPU attention. SCSI on the other hand was DMA, freeing the CPU for other tasks.

However, IDE soon gained DMA aswell. These days (with modern HW) it makes little difference from CPU usage perspective which you have. Certain specific ultra high speed applications might require SCSI still, otherwise SATA-II and RAID built with SATA devices has replaced SCSI pretty much.

[Piru]

@Tomas

Windows 95 introduced preemptive multitasking to Windows family of OSes. Earlier Windows versions used co-operative multitasking.

See Wiki: Pre-emptive multitasking and Wiki: Co-operative multitasking.

[Piru]

@tonyvdb

You may not notice but the download is not a steady stream nor will the game play full smooth frames as it will pause many times as other things are going on. Yes it is multi-tasking but its not "true" multi-tasking.

Well by that definition AmigaOS isn't true multitasking either.

[Piru]

@tonyvdb

I'm sure you would agree that the Amiga will be far more efficient at it.

I don't see much difference from technical point of view.

And as I mentioned before try formating more then one drive at the same time on a PC

And as I said already, it's more the sucky floppy controller and it being ISA HW (cpu polled crap), not software.

[Piru]

@tonydvb

I'm not sure how much of this is done by the Newtek cards but still running a video project in the switcher involves running a ton of processes at the same time. The Amiga does just fine doing that. There is no way a windows machine with as little ram and CPU speed could even dream of doing that even today.

I have to disagree really. Assuming you had the equal functionality in the software and hardware, I see no reason why equally specced windows box couldn't handle it. Windows itself requires larger memory footprint, but other than that it should be fine.

But why would you want to limit your video editing to something like the old amiga solutions? Or why would you deliberately want to run something like video editing on 10-15 year old PC?

[Piru]

@ptek

But pre-emptive is better than co-operative multitasking, right ?

Well, you can't find any co-operative multitasking OSes around anymore, does that answer your question? :-)

[Piru]

As far i understood, tonyvdb was refering to HD drive formatting, not floppy.

I have never seen ANY problems with that, the performance is just fine. Formatting HDD is hardly CPU bound, the CPU usage is 1-2% when formatting anyway.

[Piru]

@Speelgoedmannetje

Amiga hardware provided very efficient and cheap way of implementing video, but that's no OS feature. If you compare the OS multitasking (which this thread is about), pretty much all Windows since NT4 beat the crap out of AmigaOS. Thus, given equal hw features, Windows would be better.

Feel free to disagree. ;-)

[Piru]

@ptek

It's not wrong.

AmigaOS is has pre-emptive scheduler with equal priority tasks being alternated with round robin method. It's pretty much the simplest form of pre-emptive scheduler you can have.

[Piru]

@tonyvdb

There was defiantly OS involvement with video on the Amiga.

Care to detail the involvement?

[Piru]

@Speelgoedmannetje

Since a simple workbench fits on one disk, (880 kb), and since at avarage, 1 of 2000 rows of code contains bugs, how many more bugs do you think you have with a stripped compiled version of windows (wich is still a lot more megabytes) compared to a smaller workbench?

Not enough to tip the balance over to Workbench. In fact, I haven't seen my XP install crash, except when the HW was malfunctioning. Windows is remarkably stable these days.

But since I've found dozens of bugs from AmigaOS, I guess it means bad things for Windows. ?-)

Windows has free (except network connectivity) updates, too. Any bugs found from Windows have chance of getting fixed, at least.

[Piru]

@tonyvdb

Since displaying genlocked video requires 0% CPU or system resources, I'd hardly call this AmigaOS feature.

Any OS with the equal HW could do this and provide equally good multitasking at the same time.

[Piru]

@Speelgoedmannetje

Yet I haven't seen my Workbench (1.3) crashing.

It clearly means you must sell your Windows boxen and replace it with A500 running WB 1.3.

Or even better, replace it with C64 running GEOS. It has even less code that can have bugs.