MAINDEC-3 AdrTest

The MAINDEC 3 Address Test Program is a utility designed to test the address selection performance of Type 12 memory modules. It comprises two distinct parts, a "high" and a "low" test, capable of identifying both multiple addressing and failures to address across all 4096 locations of each memory unit.

The program is compatible with multi-memory machines, though not specifically designed for the Type 15 memory extend switch, and can be loaded into any memory bank.

• The high part checks addresses from 0000 (of memory "0") up to 7747 of the memory it was loaded into, occupying registers 7750 to 7777.
• The low part checks addresses from 25 to 7777 of the memory it was loaded into, occupying registers 0 to 24.

Operation involves loading the "Address Test Tape" – Part 1 loads into location 7750, and if successful, Part 2 loads into register 0, after setting appropriate Test Address Switches. The program systematically generates and writes a pattern to memory, then reads and verifies its contents through the specified address range.

Error halts (Errhlt 1 for address failure, Errhlt 2 for memory failure) provide diagnostic information, with the Accumulator (AC) containing the memory field and address, and the I/O register containing the register's contents. Operators can record this information and choose to resume testing from the error location or restart from the beginning, with the memory pattern being restored in both cases.

For troubleshooting, the program can be modified to test only a specific memory module (by adjusting the high portion's start address to 7751, disabling extend) or a particular range of memory addresses by modifying its start and stop addresses.