Legacy Hardware Support in OS

[trinopoty]

Doing some research on the net, I found that we need not provide support for PIC, PIT in OS. The hardware have become useless these days.
So, we should discourage anyone from using these legacy hardware as long as they are not specifically targeting pre Pentium 4 systems. These hardware will be completely removed in the future.

I want your views about this.

[bluemoon]

I want your views about this.

One should do all his/her research on those hardware for his/her own project and have his/her own design choice.
My opinion is no one need to discourage any other for anything.

[Combuster]

+1

It's unwise to see a particular attitude as universally superior. Some things are generally better, but even now the typical second-hand machine you'll be laying your hands on will want to be pit-pic programmed which makes your alternative infeasible for the majority until the cellar's computer is quite consistently a dual-core.

That particular bit of logic in turn includes the assumption that the best way of testing includes a dedicated second machine, and that all developers are scrooges, which obviously makes it nowhere near the universal superior solution either

[Antti]

I found that we need not provide support for PIC, PIT in OS.

It is good if we support them. Of course it is more and more important that we also support systems not having them.

It's unwise to see a particular attitude as universally superior.

I agree.

[OSwhatever]

If you don't want to write drivers for PIC and PIT, that's up to you. If you have designed your OS in a good way, you will be able to change the interrupt and timer driver with very little effort, then you can always come back later and add support for them if you want. That's what I like about software engineering, you're not stuck, you can always change.

[gerryg400]

I found that we need not provide support for PIC, PIT in OS

If you're writing an OS for a Bios-based machine you must support the PIC and PIT. They may already be in a state that requires that you do something.

Of course that something may be to carefully disable and then ignore them.

[Casm]

Doing some research on the net, I found that we need not provide support for PIC, PIT in OS. The hardware have become useless these days.
So, we should discourage anyone from using these legacy hardware as long as they are not specifically targeting pre Pentium 4 systems. These hardware will be completely removed in the future.

I want your views about this.

I wouldn't count on them being removed. Today's PCs can still run MS-D0S version 1.00. Backwards compatibility figures big in the PC world.

People can design their operating system anyway they want. You could argue that, with the advent of PCI Express, and message signalled interrupts, the I/O APIC will soon be of pensionable age.

[linguofreak]

I wouldn't count on them being removed. Today's PCs can still run MS-D0S version 1.00.

Dubiously: AFAIR, DOS 1.00 doesn't much like being booted off of anything other than 5.25" floppies, and most modern machines come with 3.5" drives if they have a floppy drive at all (which isn't to say you can't put one in, but nevertheless, most modern PC's won't run DOS 1.00 straight out of the factory).

[Combuster]

Well, if you have used an original copy of DOS 1.0 it means you have a 5¼ floppy drive somewhere, right?

[freecrac]

Well, if you have used an original copy of DOS 1.0 it means you have a 5¼ floppy drive somewhere, right?

On my board there is no connection for a floppy drive. I can only boot from a hdd, CD, or USB device.

Alternatives:
Booting a CD we can use an emulations of a floppy.
Picture of a WinImage window


For booting USB-Sticks we can the "HP usb disk storage format tool"


But i hope nobody will try to use a MSDOS version lower than version 5, because there are many applications that based on version 5 or an above version of MSDOS or compatible.

....

One member of the german dosforum suggest that there is a greater jitter using the timerinterrupt with an own ISR and with an adjusted intervall of 1000 times/second and when the USB lagacy is enabled in the bios.
With disabled he become a lower jitter lesser than 3 microseconds and with enabled the jitter is above 1500 microseconds tested on three different boards.

Dirk

[linguofreak]

Well, if you have used an original copy of DOS 1.0 it means you have a 5¼ floppy drive somewhere, right?

I've used floppy images under VirtualBox exactly because I do not have a 5.25" floppy drive somewhere.

[tom9876543]

I am guessing that MS-DOS 3.30 would be the minimum for today's computers.

I guess from memory, MS-DOS 1 and 2 wouldn't support 3.5" disk drives and/or FAT16 for the hard drive.

[halofreak1990]

Like others before me said, you should base the decision what hardware to support based on your OSs minimum system requirements.

For me, that is a Pentium 3 compatible CPU with SSE, including the original Xbox console, which still have PICs and the PIT alongside any possible APIC units.

[rdos]

Doing some research on the net, I found that we need not provide support for PIC, PIT in OS. The hardware have become useless these days.
So, we should discourage anyone from using these legacy hardware as long as they are not specifically targeting pre Pentium 4 systems. These hardware will be completely removed in the future.

I want your views about this.

Completely false. We will still see PCs without APICs for many years. Both as used PCs, and as embedded computers that often uses AMD Geode, which doesn't have an APIC. Some new embedded PCs uses Intel Atom, but that processor is not much faster than AMDs Geode, so I doubt it will replace it anytime soon.