Anyone know about this Altair Rom Basic card on ebay ?
- Well, I have one of them, I can tell you they work great. But thats about it.On Fri, Nov 20, 2009 at 6:42 AM, Dan Roganti <ragooman@...> wrote:
I have one in my Altair 8800B. It basically allows you to free up memory and run larger BASIC programs. Why? because they can run from their location in high memory. My 8800 (not the B) just has 8K BASIC in EPROMS - but since that version of BASIC must be run from 0000h, I had to hack BASIC to add a little routine to copy itself from the EPROMs address down to 0000h and then start executing itself again. This scheme works, but you end up with 2 copies of BASIC in the system, one @ 0000h and the other up in EPROM land. The ROM BASIC is larger too - I think it's a 16K card and it's running Extended BASIC - a superset of the standard 8K Altair BASIC. It also allows integer variables; thereby saving even more memory.
I have the B setup with a turnkey card with an auto boot jump to the ROM BASIC card. I've also got an ACR-88 cassette interface in the B and it works geat with the ROM BASIC. The B is my "BASIC Machine" - that's all it does and it does it well. I can run 40K+ monster Star Trek programs in BASIC.
These cards are rare - so the price may be right. But if you just want the functionality, zapping some chips is the way to go...
I haven't seen a download of the ROMs out on the net. Let me know if you find one. If not, let me know too, I'll see what I can do on this end to extract the data to a file.
- The MITS price list includes two boards the 88-RMB ROM BASIC I and 88-RMB2 ROM BASIC II. The Jan 78 MITS memo ROM BASIC Operation mentions the "Preliminary" 16K Extended ROM BASIC Board.
The 88-RMB ROM BASIC I board does not have auto-start logic and was used in conjunction with the Turnkey Module board. My assumption is that the 88-RMB ROM BASIC I board would work in a front panel machine without a Turnkey board.
I assume the 88-RMB2 ROM BASIC II has auto-start logic. I've only seen examples for the 88-RMB ROM BASIC I board. Does anyone know if the 88-RMB2 ROM BASIC II board was actually produced? The 88-RMB ROM BASIC I board is fairly rare.
Another assumption is that the ROM BASIC board was intended for the Attache and died at the same time. The Attache did not sell well and Pertec focused on BASIC for business disk systems.
The memo "ROM BASIC Operation" and "Preliminary Attache User's Manual" provide a small amount of information:
ROM BASIC may be supported by an ACR (audio cassette recorder) for storing and loading of data only. ROM BASIC is the same Extended BASIC as on the disk without special disk functions.
Note: The ACR board used in the Attache was the 88-UIO.
To load BASIC from ROM, proceed as follows:
a) ROM BASIC does not dump into RAM memory; therefore it is actually not loaded in the normal sense. ROM BASIC occupies the top 16K of memory, and care must me taken to ensure that the turnkey PROM and RAM addresses do not conflict with ROM BASIC or other memory boards.
b) PROM and RAM addresses must be below 140000(octal), and not conflicting with other memories. Note: A Turnkey Module in a MITS 300 system would occupy the top 16K of memory.
On turnkey boards without the 88-SYS-CLG mod , set the position of the 1K RAM block just above whatever the rest of RAM may be in the system. Note: A turnkey board with the 88-SYS-CLG modification has the 1K of RAM disabled. The RAM was removed on the latest board revision.
Note: For example, a 32K system becomes 33k with an unmodified early revision turnkey. Maximum RAM would 46K + 1K from turnkey + 1K of PROM. A modified turnkey might allow 47-48K RAM. The 88-SYS-CLG makes the PROMS phantom and 48K RAM may be possible.
Set the PROM address to just below ROM BASIC at 47K. Note from memo: Any Proms on the Turnkey Module can no longer be used.
Note: My assumption is the MITS PROMS cannot be used because they were coded to be in the top 16K. My assumption is that custom proms could be used.
c) SIO address 020 (octal)
Note: This is the standard MITS console port. The port could be on a turnkey board or 88-2SIO. Watch for address conflicts if you have both boards.
d) Start address 140000 (octal).
Note: 140000 (octal) would be the start address set on the turnkey or address switch settings on a front panel.
ROM BASIC runs in ROM at the top 16K of memory. After starting BASIC using an 88-SYS-CLG modified Turnkey Module, an OUT to port FF should disable the PROMs at 47K. BASIC starts at 0 and checks up until memory cannot be changed. R/O memory indicates a gap, PROM or ROM. With the PROMs disabled BASIC can find the RAM that overlapped before the OUT to FF. That assumes there are no gaps in RAM below the Turnkey Module.