MCP (Master Control Program) was the control program for Fujitsu's medium general-purpose computers FACOM 230-20 and FACOM 230-30, and was made available in three models: MCP I, MCP II and MCP III. MCP II was the first control program for the company’s medium general-purpose computers to realize multiprogramming, and was completed in December 1966.
The following is the history of MCP development, together with an overview of MCP II.
Previously, in program development, compile process and execution process were independent of each other, and switching between the two processes required considerable time and labor. To continuously execute jobs, the control program MCPI (Master Control Program I) was developed. Subsequently, MCP II and MCP III were successively developed. MCP II realized multiprogramming in order to increase the use efficiency of the computer (FACOM 230-20 and FACOM 230-30), and MCP III enabled small-scale real-time processing.
Table 1 shows the features and the completion dates of MCP models.
|Name||Features||Required core memory||Completion date|
|MCP I||Control program for batch processing
The control program itself was placed on a magnetic tape or magnetic disk in order to avoid it occupying the memory during execution.
|32/65k digits||October 1965|
|MCP II||Control program that realized multiple programming||65k digits||December 1966|
|MCP III||Control program that enabled two concurrent processes by improving MCP II. Two processes are one small-scale real-time process and one batch process, or two batch processes. The memory was divided into a batch program area and a real-time program area. The real-time program area was further divided into 16 segments to overlay programs.||32/65k digits||June 1967|
MCP II was the first control program for Fujitsu’s medium-scale general-purpose computers to adopt multiprogramming, and provided the following features:
The MCP II multiple programming system consisted of control program MCP II, a translation program (assembler FASP) under control of MCP II, service programs (FASP-CHECK, EDIT, UTILITY and SORT/MERGE) and user-created programs written in FASP language.
Table 2 shows the hardware equipment required for MCP II.
|Item||Name of equipment||Number of units/capacity||Remarks|
|1||FACOM 230-20 (or 230-30) central processing unit||1 unit|
|2||Memory unit||65k digits|
|3||Console/Typewriter unit||1 unit|
|4||Paper tape reader or card reader||1 unit|
|5||Magnetic drum unit||1 unit or none||1 unit recommended|
|6||Magnetic tape unit||None or 2 units||2 units required if no magnetic drum unit.|
MCP II consisted of two parts: MCP II supervisor program and MCP II monitor program.
The supervisor program was the core of the system, and the monitor program and the job programs (including the translation program and the service programs) were all executed under control of the supervisor program. The supervisor program consisted of two parts: an interrupt processing routine and SWITCHER, which provided the function to switch running programs.
The monitor program consisted of four parts: 1) keyboard instruction processing routine, 2) SCHEDULER, 3) INITIATOR and 4) TERMINATOR. The monitor program controlled interaction with the operator, management of job flows and management of some kind of the I/O devices.