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+--- Thread: New later version of Microworld Basic 5.00 found (/thread-419.html)
New later version of Microworld Basic 5.00 found - ChickenMan - 13-01-2022
Thanks to kimjohn for forwarding his original Kit Microbee to Microbee Technology to be repaired where I was able to dump the 4 x 2532 eproms containing Basic 5.00. A USB GQ-4x4 Programmer was used to dump these roms.
These were then compared to the ones we already have dumped earlier last year, and Rom C was found to have 2 bytes different, Rom A, B & D were identical except the serial number in D. Was the difference because of bit-rot or an updated version because the 2 different bytes appeared to be just swapped around -
Original set had at B765 - B7 & B76E - F7
This new set had at B765 - F7 & B76E - B7
Thanks also to "someone" who was able to confirm the difference in ROM C is a correction of the speaker driver that was carried on to 5.10. The original order left the speaker on! Typical of Applied Technology at the time where they would make small code changes on the fly without changing the version number. So we now have 2 slightly different versions of Basic 5.00.
The serial numbers consist of 4 hex bytes encoded in BCD with the first byte being the year. The following byte is sometimes but not always a checksum byte followed by its serial number. The first 5000 or so Microbees had their BASIC ROMS burnt from 3 DGZ80 S100 systems.
Original set had at BF00 - 81 00 02 50
This new set had at BF00 - 81 00 03 83
So these Roms were produced in late 1981 ready for the Microbee launch in Feb 1982 with Serial Numbers 250 and 383 respectively. These Serial numbers are used to differentiate the 2 versions. So the current set of Basic 5.00 were renamed with Serial Number 250 added to is name.
Also onboard was EDASM as 2 x 2532 eproms and when dumped, they are identical to what we already have in the repository.
So in the MbeeTech Repository in the Software/ROMs/Basic folder we placed
basic_5.00_sn250.zip that contains
basic_5.00_a.rom
basic_5.00_b.rom
basic_5.00_c.rom
basic_5.00_d.rom
basic_5.00_sn250.rom <--- 16k file for use in emulators
basic_5.00_sn383.zip that contains
basic_5.00_a.rom
basic_5.00_b.rom
basic_5.00_c.rom
basic_5.00_d.rom
basic_5.00_sn383.rom <--- 16k file for use in emulators
RE: New later version of Microworld Basic 5.00 found - ChickenMan - 31-05-2024
MbeeTech recently obtained an original 16k Microbee Kit in the early Black case. It had the 4 Basic roms (all 2532 eproms) only and had lost their stickers covering the window. The 'bee was powered up and it booted to Basic 5.00. So the 4 Basic roms were dumped, thanks MbeeTech, to see if they differed from the 2 sets we already have as above. Comparing the dumps with the basic_5.00_sn383 set above, they were an exact match except for the serial number, 321. So this gives conformation that the 2 set of roms dont have any rom rot.
It was decided to include them in the Repository because of their scarcity.
So in the MbeeTech Repository in the Software/ROMs/Basic folder we placed
basic_5.00_sn321.zip that contains
basic_5.00_a.rom
basic_5.00_b.rom
basic_5.00_c.rom
basic_5.00_d.rom
basic_5.00_sn321.rom <--- 16k file for use in emulators