Ampex ARM10

The Ampex ARM10 was main memory for the PDP-10, which connected to the external memory bus. There were several different forms (certainly at least three), sharing only the name:

• the ARM10, a 256K word core memory unit (reported on the KA10 MIT-AI ITS machine);
• the large ARM-10L was also a core system (one was attached to the KL10 MIT-MC ITS machine)
• the ARM-10LS, known from DEC documentation, which seems to have been, effectively, an ARM-10L which used DRAMs instead of core

Finally, there are reports of one which provided "four mega-words of ECC-protected semiconductor memory (using 64K DRAMs)"; that was likely the Ampex ARM20.

External links

• ARM 10L memory - ARM-10L unit at the Computer History Museum
  • Magnetic core memory - core module
  • Magnetic core memory - core module
• ARM 10LS memory - ARM-10LS unit at the CHM
• KL10 Maintenance Guide Update (EK-OKL10-MG-004) - the ARM-10LS is covered on pp. 163-196 of the PDF