Computer history: Background on Digital Equipment Corp. equipment used at TNO Waalsdorp

 

Digital Equipment Corp. equipment used at TNO

Below you find the specifications of some of the Digital Equipment Corp. (DEC) computer systems and equipment which we used at TNO Waalsdorp between the seventies and mid-nineties.

 

Type/Model	Description
CONTROLLERS
KDB50-C	Disk controller.
KDM70-AA	Disk/tape controller. Capable to drive 8 RA disks, TA tape drives (max. 2). Maximum of 700 I/Os per second.
UDA5	Disk controller. A low-performance UNIBUS-based disk controller for RA disks.
HSC5X-DA	Disk/tape controller.
DISK SUBSYSTEMS
RD54	Winchester disk: 159 MB for VAXstation 2000.
RA80 disk drive	121 MB fixed media Winchester disk drive. This physically large drive (14-inch platters, in a heavy enclosure 10.5″ x 16″ x 36″) was very common at DEC sites. Most of the RA80s were installed in three-level high cabinets. 1.2 MB/s peak transfer rate; 33.3 ms average access time; 25 ms average seek time; track-to-track seek time 6 ms; 8.33 ms latency; 3600 rpm; seven data and 1 servo disk surfaces; 1,092 tracks/surface; 31 sectors/track (16 bit words); 512 bytes/sector
RA81	456 MB Winchester disk drive. This physically large drive (14-inch platters, in a heavy enclosure maybe 10.5″ x 16″ x 36″) was very common at DEC sites. Most of the – in 1982 announced – RA81s were installed in three-level high cabinets. 2.2 MB/s peak transfer rate; 36.3 ms average access time; 28 ms average seek time; track-to-track seek time 6 ms; 8.33 ms latency; 3600 rpm; seven data and 1 servo disk surfaces; 2,496 tracks/surface; 51 sectors/track (16 bit words); 512 bytes/sector.
RA82	608? 622? MB Winchester disk (DEC mentioned both values).
RA90	1.2 GB Winchester disk.
SA600	2.4 GB disk array based upon 2 RA90 disks.
TAPE SUBSYSTEMS
TU80	Magnetic Tape desktop unit. 25 ips start/stop mode; 100 ips streaming mode; 1600 cpi; max. 160 kB/s transfer rate. 192 ips rewind speed or 2.5 minutes for a 2,400 ft reel. It came with its own UNIBUS tape controller.
TU81E	Magnetic Tape desktop unit. 25 ips start/stop mode; 75 ips streaming mode; 1600 and 6250 cpi; max. 468 kB/s transfer rate. 192 ips rewind speed or 2.5 minutes for a 2,400 ft reel. It came with its own UNIBUS tape controller.
TK50	TK50s were DEC-proprietary cartridge tapes that measured about 5″ x 5″ x 1″. The cartridges were expensive–about $35–but quite reliable. Our TK50 drive came, of course, with its own UNIBUS controller. A TK50 could hold about 95MB.
TA90E	The TA90E cartridge tape subsystem was derived from an IBM 3480 cartridge tape drive. 200 MB/cartridges; using compression up to 600 MB/cartridge. Unattended operation possible as 12 cartridges could be inserted in two stackers. Read/write speed: 78.7 ips. Max. data transfer rate 2.7 MB/s. Rewind speed 157 ips or 48 sec (full cartridge). 18 tracks; 38 kB/inch.
UNIT RECORD
DATA COMMUNICATION
TERMINALS
VT100 series	More on the VT100 can be found (off-site) at: https://en.wikipedia.org/wiki/VT100
SYSTEMS
PDP 11/34	A system which we used for driving various types of input/output devices such as papertape, floppies, etc,., the Data Conversion Station.
PDP 11/60	PDP 11/60
microVAX 3500	The microVAX 3500 processor has two levels of cache memory: an 1 Kbyte 2-way set associative cache is built into the processor chip itself, and an external 64 Kbyte direct mapped cache. Overall cache hit rate: 95 to 99%. If there is an on-chip (first level) cache hit, the external memory bus is not used by the processor. The first level cache responds to a read in one machine cycle (90ns), while the second level cache responds within two cycles. Both caches can be configured as caches for instructions only, for data only, or for both instructions and data. In a single processor system, a mixed cache is typical; in systems with several processors and shared memory, one way of ensuring data consistency is to cache only instructions (which are not modified). Then all data must come from main memory, and consequently whenever a processor reads a data word, it gets the current value.
VAX 11/750	VAX 11/750 Central Processor System: 32 bit single precision and 64 bit double precision floating point. 4 KB direct mapped memory cache. 512-entry address translation buffer. 8-byte prefetch instruction buffer. A Floating Point Accelerator (FPA) could be added as an option. 320 ns microcontrol store instruction time. System data transfer rate 5 MB/s max. 8 MB ECC memory, plus 1 MB increments; 800 ns 32-bit read; 640 ns per 32-bit write. More on the VAX 11 series: https://en.wikipedia.org/wiki/VAX-11
VAX 8350	The VAX (Virtual Address eXtension) 8350 was a double-CPU 8300-CPU system. Each CPU had a processing power of 1.2 VAX-units of performance (VUP’s) or MIPS. ZMOS technology. 13.3 MB/s max. I/O throughput. 2* 8 KB cache. 160 ns cache access time.
	VAX 6000/310: CPU 6000-310 processor. Floating point processor speed-up. 32 MB memory. 2 VAXBI I/O-channels. 296 MB tape unit and controller. 3.8 VAX-units of performance (VUP’s) or MIPS. CMOS technology. 60 MB/s max. I/O throughput. 1 KB first level CPU-chip cache and 256 KB onboard cache. 60 ns cache cycle time and 120 ns on board.
VAX 6000/410	VAX 6000/410 CPU: 7.0 VAX-units of performance (VUP’s) or MIPS. CMOS-3 technology. 80 MB/s max. I/O throughput. 45 MFLOPs double precision and 90 MFLOPs single precision. 2 KB first level CPU-chip cache and 128 KB onboard cache. 28 ns cycle time.

Link to specifications on old DEC VAX systems as well as to the timeline.

 
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