28-09-2021, 01:05 AM
Hi Chesh,
My bad, I should have told you to swap ROMs G & H.
I will need to correct the previous post as I stuffed it up, maybe that is where your confusion is comming in.
The second bank (top 64K are as follows)
ROM E - IC25 Lower = Pak1 - Upper = Pak9
ROM F - IC24 Lower = Pak2 - Upper is reserved for the PC85b MENU
ROM G - IC23 Lower = Pak3 - Upper = Pak11
ROM H - IC22 Lower = Pak4 - Upper = Pak12
ROM I - IC27 Lower = Pak5 - Upper = Pak13
The Upper bank of ROM F is the Menu this is the decoded PAK 10 however cant be directly accessed it will come up with a "Option not Fitted" error in basic. Menu must reside in the upper bank (64K of ROM F it can't be located anywhere else. Normally the lower 64K of the F ROM is the Spreadsheet program.
Shell resides in the lower 64K of ROM I, and must be in this position, this ROM can be called from basic with PAK5.
So in short ROM's F and I can't be swapped with any other ROMs they must remain in those positions and in their respective banks.
Although I have not confirmed it I think that ROM E lower bank must also be in the ROM E position for BASIC's Command Help to function correctly.
Hopefully I have it right this time.
Can you get back to a simple system where you were booting to the shell again?
Ernest
My bad, I should have told you to swap ROMs G & H.
I will need to correct the previous post as I stuffed it up, maybe that is where your confusion is comming in.
The second bank (top 64K are as follows)
ROM E - IC25 Lower = Pak1 - Upper = Pak9
ROM F - IC24 Lower = Pak2 - Upper is reserved for the PC85b MENU
ROM G - IC23 Lower = Pak3 - Upper = Pak11
ROM H - IC22 Lower = Pak4 - Upper = Pak12
ROM I - IC27 Lower = Pak5 - Upper = Pak13
The Upper bank of ROM F is the Menu this is the decoded PAK 10 however cant be directly accessed it will come up with a "Option not Fitted" error in basic. Menu must reside in the upper bank (64K of ROM F it can't be located anywhere else. Normally the lower 64K of the F ROM is the Spreadsheet program.
Shell resides in the lower 64K of ROM I, and must be in this position, this ROM can be called from basic with PAK5.
So in short ROM's F and I can't be swapped with any other ROMs they must remain in those positions and in their respective banks.
Although I have not confirmed it I think that ROM E lower bank must also be in the ROM E position for BASIC's Command Help to function correctly.
Hopefully I have it right this time.
Can you get back to a simple system where you were booting to the shell again?
Ernest