KA650 CPU

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KA650
Summary
OS support (VMS): V4.7A or later
OS support (ULTRIX): ULTRIX V2.2
CPU Details
CPU name (VMS): KA650
CPU module: KA650
Module: M7620 [3]
Number of processors: 1
VMS DCL CPU: 10
VMS DCL XCPU: 1
SID: 0A000005
XSID: 01530101
CPU chip: 78034 (CVAX) [1]
FPU chip: 78132
CPU technology: CMOS
CPU cycle time: 90ns [4]
Instruction-buffer: 12 bytes [1]
Translation-buffer: 28 entries [1]
Cache: 1KB (90ns) [1]
Backup cache: 64KB (180ns longword, 270ns quadword) [4]
Compatibility mode: No
Console processor: CPU
Console device: None
Firmware version: V5.3
Console speed: 300 to 38400
Memory
Minimum memory: 8MB
Maximum memory: 64MB
Memory checking: 32 + 7 bit ECC [4]
Memory cycle: 450ns longword, 720ns quadword [4]
I/O
Q-bus: 1 @ 3.3MB/s
Performance
VUPs: 2.7 [2]


The KA650 is the CPU used in DEC's MicroVAX III. It is a single quad-height PCB which plugs into a QBUS backplane. [4]

The KA650 is implemented using the CVAX with floating point instruction support provided by the CFPA, main memory control provided by CMCTL, and various system support functions by the SSC.

There are two versions of the KA650:

  • KA650-A (M7620-A): Time-Sharing CPU
  • KA650-B (M7620-B): Workstation / Server CPU

The only differences between the two CPUs are the system ROMs:

  • KA650-A: 23-192E7 and 23-193E7
  • KA650-B: 23-194E7 and 23-195E7

You need different VMS software licenses for the two KA650 versions.

For information on KA650 revisions and compatible options see: KA650 Revision Control.

Memory Subsystem

The KA650 memory subsystem is detailed elsewhere: KA650 Main Memory System.

References

[1] "CVAX-based Systems", Digital Technical Journal, Vol 1 No 7, August 1988.

External links