This folder contains Altair 8K BASIC and Altair Extended BASIC updated to use
the 2nd port on an 88-2SIO (12h/13h) for cassette I/O instead of the standard
88-SIO port at 6/7 used by the Altair Cassette Interface. This update includes
the bootstrap loader, the checksum loader on the tape, and the cassette I/O
routines within BASIC.

To load 8K BASIC, use the LDR8K40 bootstrap loader present in this folder. To
load Extended BASIC, use the LDREXT4x bootstrap loader. Set switches A15-A12
to 0001 to use port A on the 88-2SIO as the console. Set switches A11-A8 to
0110 to select port B on the 88-2SIO as the load port (cassette).

You can also load this tape with Martin Eberhard's enhanced version of the MBL
PROM, "MBLe" (the original MBL PROM won't work). Note also that AMON on the
88-2SIOJP has the equivalent of MBLe at its standard address of FE00. To load
8K or Extended BASIC, set A15-A12 to 0001 to use port A on the 88-2SIO as the
console. Set A11-A8 to 0110 to select port B as the load port (cassette).

Martin Eberhard's MBLe PROM can be found here:
https://deramp.com/downloads/altair/software/roms/custom_roms/M%20Eberhard%20Improved%20ROMs/

You can write this 8K BASIC tape or Extended BASIC tape to cassette using the
WRTAPE utility on the "MITS Tapes" CP/M disk image found in the "CPM Utilities
for Altair Cassette" up one folder level from this folder.