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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Amiduffer on March 01, 2007, 08:06:51 PM
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Harkening back to Motorollins way cool experiment of putting OS3.9 on an EPROM THREAD (http://www.amiga.org/forums/showthread.php?t=22929) I was wondering about other Amiga's. I have a chance to get a cheap A500, and was wondering about the possibility of putting 1.3WB on the EPROM?
I haven't owned one of these in a long time, so, is that physically possible?
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Amiduffer wrote:
Harkening back to Motorollins way cool experiment of putting OS3.9 on an EPROM THREAD (http://www.amiga.org/forums/showthread.php?t=22929) I was wondering about other Amiga's. I have a chance to get a cheap A500, and was wondering about the possibility of putting 1.3WB on the EPROM?
I haven't owned one of these in a long time, so, is that physically possible?
Err... the A500 will have the 1.3Kickstart ROM in it already...
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bloodline wrote:
Err... the A500 will have the 1.3Kickstart ROM in it already...
Unless he actually meant to say: Put both kick and workbench 1.3 into EEPROM.... or actually meant only kick but with the contents of the latest available setpactch for kick1.3. In both cases it would make somewhat sense.
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To tell you the truth, I'm still somewhat confused about how the hardware functions, although, with some work, maybe I'll get the hang of it someday. :hammer: What does the ROM chip actually DO, or how does it work, in combination with Workbench? If you can, please be as un-technical as possible. Thanks.
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Unless he actually meant to say: Put both kick and workbench 1.3 into EEPROM....
With an A1000, that had no Kickstart ROM, there was a product I used extensively called KickWork that included both the Kickstart and the Workbench on one floppy. The Workbench was modifiable so that hard disk devices could be added, the Startup-Sequence edited, etc. (Of course, it helped that Kickstart was only 256K in those days.)
These days, it's easy to get EEPROMs bigger than 2 floppys, but I don't know if an A500 could access much more than 500K in that memory region. Plus, usually KS looks for a disk device to load WB. I do have a device that starts an A500 from ROM that goes on the 86 pin expansion, that came from a arcade game, but it may be set up as a Zorro device.
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I get it now: you were thinking you could put the ENTIRE Amiga WB1.3 on an EPROM and therefore not need to boot Workbench from disks at all.
That's not what Amiga Kickstart ROMs do.
The Kickstart chips hold just the bootcode, some basic libraries and functions of the OS (beyond that it gets too technical for me), the OS kernal. This gets the Amiga going, then it looks on the disk to load the full operating system into RAM.
Even with Motorollin's KS3.9 EPROM, that isn't ALL of Amiga OS3.9 on a chip. He just put the patched kernal, etc. the contents of the file AMIGA OS ROM UPDATE that came with OS3.9 onto the an EEPROM(s). It was basically the 3.1 Kickstart chips patched with the OS3.9 Update files on a chip so you didn't need to do the soft reset upon bootup. But even with these new KS chips you still need to load the OS from disk.
Basically, if you turn on an Amiga and have no drives attached, you can get into the early startup menu, and boot without a startup sequence (you will get a CLI like screen). That is what is contained in the Kickstart chips.
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Ignoring the technical issues, it is a bit pointless to put workbench in EPROM. If you want silent operation and fast Workbench access... get an A600/A1200 and a PCMCIA flash card!
Looking closer, just for Kickstart type stuff, I am not 100% sure if the A500 motherboard can take larger EPROMS. You'd have to create a harness to the Gary chip / 68000 to access the extra ROM.
The A1200 and A4000 can both take (and utilise) 1Mbyte EPROMS.
Redskull once did an A500 flashROM adapter that is available as schematics on Aminet.
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Ah! That makes things a little more understandable. Thanks everyone.
Alexh, I already have a A1200 and A3000D with the standard HD and accelerator, so things are satisfactory in that area. My bringing up this topic is the possiblity of getting a stock A500 nearby, and i'm thinking of possibilities of what I could do with a slightly beat up miggie, one that you wouldn't mind hacking around with. The mod jobs that I've seen other people do, are quite inspiring.
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actually, it is possible to use a 1mb rom A500+'s and (possibly) A600. I used a 27C800 rom to write a 1mb rom as explained in this thread (http://www.amiga.org/forums/showthread.php?t=25665) and it works fine. However, I prepared a 3.9 rom, with exec 45 which was useless on my stock 68000 A500 so I felt like an idiot :).
AFAIK, putting in whole wb 1.3 would be a really difficult job cause what I get from doobrey's comments is that the code inside the rom should be rommable code. You just can't copy stuff in there and expect it to work. I'ld be really glad if someone could explain the notion of rommable though. There's lots of space in a 1mb rom we could fill in :) (like a fat95 filesystem ? or cf.device ? or some whdload libs ?)