M-1118 Aug61

This Permanent Memorandum (M-1118), dated August 11, 1961, from Digital Equipment Corporation's Computer Division, provides a detailed inventory of the types and quantities of components used in the PDP-1 computer system.

The document is structured into three tables:

1. Table I: Components of Plug-In Modules Used in PDP-1 lists 35 different types of plug-in modules (e.g., inverters, decoders, flip-flops, amplifiers, sense amplifiers). For each module type, it specifies the critical and non-critical quantities of its internal components, such as various types of resistors, capacitors, transistors (e.g., MA80, 2N1305, 2N1754), and diodes (e.g., D-001, D-662). It also indicates how many of each module type are utilized in the standard PDP-1 (totaling 544 modules), the Automatic Multiply and Divide Package (totaling 35 modules), and the 16-Channel Sequence Break System (totaling 69 modules).

2. Table II: Components of Power Supplies Used in PDP-1 describes four different power supply types (e.g., +10 volt, dual variable 20 volt, dual 15 volt 6 amp, memory temperature compensated supply). For each supply, it details its constituent components, including transformers, various diodes, electrolytic capacitors, resistors, fuses, variacs, and voltmeters, with critical and non-critical quantities. The standard PDP-1 utilizes 8 power supplies.

3. Table III: Summary of Components Used in PDP-1 provides an aggregated total count of all critical and non-critical components across all modules and power supplies mentioned in the previous tables. This summary breaks down the total quantities for categories such as:

   • Transistors: 3,535 (e.g., MA-80, 2N1304, 2N1754)
   • Diodes: 6,289 (e.g., D-001, D-662, 1N1217)
   • Resistors: 11,424 (carbon, wirewound, power)
   • Capacitors: 4,175 (dual 1000 volt, aluminum electrolytic, ceramic, mica, mylar, tantalum solid electrolytic)
   • Transformers: 426 (2-winding pulse, 4-winding pulse, Triad F-40X, Resonant DEC 100-X-1010)
   • Delay Lines: 56
   • Trimpots: 46
   • Fuses: 5
   • Variacs: 4

In essence, the memorandum functions as a comprehensive bill of materials, detailing component types and quantities for the base PDP-1 system and its key expansion packages in a structured, hierarchical manner.