【Fujitsu】 FACOM M-100 Series of Large Mainframes

The FACOM M-100 series was the first large mainframe series under Fujitsu’s FACOM M series of mainframes. The series was announced in November 1974. The series had three models: the very-large FACOM M-190 and the large FACOM M-180II and FACOM M-160. The primary characteristics of this series are given below.

(1)IBM S/370 architecture
It employed the international standard IBM S/370 for its basic architecture.
(2)Large scale integrated circuits (LSI)
Using LSI throughout, it achieved an outstanding cost-performance ratio and high performance, while reducing power and space. The LSI was at the highest level in the world for practical devices, with a maximum of 100 gates per chip, and an average on-chip delay time per gate of 700 picoseconds. By using such LSI throughout the system, this series achieved a quantum leap in processing speed, while improving reliability and achieving power and space savings
(3)High-speed address translation architecture
The M-100 series was equipped with a translation lookaside buffer (TLB), a hardware module for translating the series’ 16-megabyte virtual address space into physical addresses at high speeds. The series also came with a segment table origin (STO) stack to handle at high speeds the multiple virtual storage spaces supported by mainframe operating systems. (See Figure 1.)
(4)Dynamic address translation (DAT) channel architecture
The DAT channel architecture made it possible to read and write data from I/O devices directly to virtual memory spaces, resulting in a five to 20 percent improvement in system performance compared to if DAT channel architecture were not used. Online systems, in particular, benefited greatly from this architecture.
(5)Service processor (SVP)
In addition to hardware-based functions for auto recovery and auto correction, the M-100 series came with a SVP independent of the main CPU to enhance the machines’ reliability, availability, and serviceability functions. The SVP’s specific functions are as follows.
  • Console functions for the operating system.
  • Operation panel functions: The main panel on FACOM M-100 series machines had almost no lights or switches, so this function was used to operate the computer using a display device connected to the SVP.
  • Maintenance panel functions: Service personnel (customer engineers) made use of the operational status information and test tools available from the SVP.
  • Remote maintenance functions: The SVP could be connected to a service center by a communication line.
(6)Software for online databases
M-100 series machines were furnished with the Advanced Information Manager (AIM), a comprehensive online database management software package that closely integrated the functions of an online network and the functions of a sophisticated database.

Figure 1: TLB and the STO stack

Figure 1: TLB and the STO stack

Large FACOM M-100 Series Specifications
Model name M-160 M-180II M-190
Announcement date May 1975 September 1975 November 1974
Size Large Ultra-large
CPU Number 1 1 or 2
Main device 100 gates/chip, delay time 700ps/gate ECL LSI
Buffer memory - 8 KB, 16 KB
Bipolar ICs
Bipolar ICs
Address translation architectures TLB TLB and a STO stack
Memory unit Memory device N-MOS IC memory (4K bit/chip)
Cycle time 360ns/8B 350ns/8B 480ns/32B
Cycle time 256 KB to 4 MB Single CPU model:
512 KB to 4 MB
Multi CPU model:
1 to 8 MB
1 to 16 MB
Check function ECC (1bit automatic error correction, 2bit error detection)
Maximum number of channels 8 12/CPU 16/CPU
Remarks There were also enhanced models, the M-160AD and M-160F There was also an enhanced model, the M-180IIAD There was also a successor model, the M-200

(Note) The above specifications are from the time of announcement, and may have been changed due to later improvement.

LSI used by FACOM M-160/M-180II/M-190, which is ECL (emitter-coupled -logic) LSI with 100 logic gatesMCC (Multi-chip-carrier), mounting max.42 LSIs