SqueakOS

JohnMaloney at earthlink.net JohnMaloney at earthlink.net
Thu Oct 3 15:50:07 UTC 2002


Re:
>And of course, this wonderful code is buried somewhere to never be used 
>again. The wonders of propietary closed source software. Interval has 
>donated some things, but if they didn't want to use a RTOS Squeak, what 
>makes them think someone else ever will? ( Why hold on to dead project 
>code? No one is gonna buy it! Set it free! ).

One of the achievements of the Interval SqueakOS was to allow device
drivers to be written in Squeak. That's a pretty fancy trick, and they
pulled it off.

However, the current Squeak can and has been used as it's own operating
system with device drivers written in a combination of C and assembly
language. It has been done at least twice, once at Disney for a StrongARM
developer's board and once at Mitsubishi for an experimental processor
called the M32R/D. In both cases the development effort took about six
weeks, most it spent writing device drivers for the mouse, display, clocks,
and the Flash memory file system. The M32R/D Squeak even had a sound driver,
and Alan used it to give a demo of an early version of the EToy system,
to the great amazement of the Mitsubishi executives.

So, it's really quite easy to get Squeak running on bare hardware.

But...

Once you've done it you realize that there is a lot of hardware out there,
like wireless cards, cameras, drives, etc. Hardware specs for these
devices are often unavailable to developers because the vendors typically
supply their own device drivers for the standard OS's. So even if you
have the time to write your own device drivers, you may lack the
necessary documentation.

My conclusion is that, even if you don't want an OS for any other reason,
it has definite value as a standard for device drivers. Assuming you can get
the OS to give Squeak most of the processor cycles, the main advantage
of ditching the OS is to get back some memory. On handheld devices,
that can be significant, but in most cases I think it's probabably more
practical to co-exist with an OS so you can use it's device drivers.

The Interval project was a special case. They were building their own
custom hardware, so they HAD to write their own device drivers, and
they had a large team of both hardware and software engineers.

	-- John





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