From: Ben A L Jemmett <[EMAIL PROTECTED]>
>> Then basicly, putting an OS such as Linux on a game machine such as
>> the dreamcast has only two reasons:
>>
>> 1)Allow an easier port of Linux programs to the Dreamcast enviroment
>> (Silly excuse. Nothing prevents them of making a compiler that makes
>> ROM
>> files instead of ELF)
>Uhr, if you could make a ROM file containing your program, it'd crash pretty
>quickly, since the services the kernel provides aren't there.
Only if you place it where the BIOS was, or fail to load the OS.
>No filesystem, no memory management, no scheduler => no processes, no device
>management, no networking or communications of any sort, and no console so
>no user I/O! It'd be like burning something like the in-memory image of
>EDIT.COM to ROM without DOS - you wouldn't get very far.
There's no reason why you can't run a block of code from a ROM chip after
the OS is running.
Assuming you have a block of code that works on the OS in question, you
should be able to run it from a ROM, too. You need to be able to start
it by some means, such as a hot key - for example hitting <Del> to run the
SETUP program during Startup. You could always use a Debugger, such as
DOS's DEBUG. If the code is self-modifying, you will have to copy it to
RAM before it will run, but g=<starting address> will run it. Ideally,
all this should be built into the code before copying to the ROM chip.
Think of the original PC, which had the BIOS code start at F000:FFF0
(Where the code is telling the CPU where to jump to the real start of the
code.) When the BIOS got around to checking the A: drive for a boot
sector, if it failed to find one, it jumped to the starting point of the
other chip and ran BASIC. If you put your code in the same place, it
should run the same way.
There were 5 other sockets, addressed A000:0 to FFFF (in blocks of 64 K),
B0000:0 to FFFF, up to E000:0 to FFFF. The BIOS, of course was in
F000:0 to FFFF. Now, BIOS chips come in bigger blocks, and there is seldom
another socket - but there could be unused space on the BIOS chip, which
is now often flashable.
>> 2)"Because we CAN". That looks like the real reason. And i'm all for it!
>The true reason behind all geekdom - long live useless projects!
I can think of one use... Imagine how quickly your system could boot, if the
OS was already in ROM, instead of having to be read from a relatively slow
drive.
On the other hand, the thought of Windows ME on a motherboard in 256 K EEPROM
chips makes my eyes go fuzzy...
Boyd Ramsay
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