SJ Research Hard Disc File Server

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Introduction

The SJ Research HDFS (Hard Disc File Server) was SJ Research's first Econet file server. It is notable for both its size and weight (it is approximately 52 x 44 x 18 cm). The HDFS could support up to 80MB MFM hard disc, a serial and parallel printer and a 20MB tape drive.

The HDFS configuration is:

• 2 x Z80B 6MHz CPUs
• 64KB + 128KB RAM
• 256 KB cache RAM
• 20 MB hard disc with options up to 80MB,
• 20MB tape cartridge drive
• Built in priner server with 2 independent print channels (parallel and serial)
• Built in real time clock
• Supports up to 256 user accounts
• Econet level 2 file server protocol support.

The HDFS automatically date and time stamps files when saved or updated and supports disc space accounting which allows disc space limits to be set for each user. In 1986 an 80MB HDFS would have cost you £9,000 (£7,200 for education users)!

Documents

Here is a brochure describing the SJ Research HDFS .
Here is the SJ Research Hard Disc File Server System Manager's Manual v0.22 17-7-85 .

HDFS

 SJ Research HDFS (front)

The front of the SJ Research HDFS has the tape drive in the bottom left, the LEDs in the top right are: Change Tape, Tape Active, Disc Active, System Failure, No Clock, Boot Error, Printer Error, Configuration and online. The mode key-switch is at the bottom right.

  SJ Research HDFS (right)

  SJ Research HDFS (back)

The back of the HDFS shows:

• the power in in the bottom left
• the serial number (HDFS/0060) next to the pwoer in
• the Econet socket in the top left
• the Serial printer port next to the econet socket
• the Enter configuration mode switch above the serial printer socket
• the fan in the middle
• the parallel printer socket in the top right
• the serial printer baud rate slde switch is next to the parallel printer port.

 SJ Research HDFS with top cover removed 

Removing the top cover from the HDFS shows the main circuit board.the ribbon cable on the left is connected to the tape drive and the ribbon cable at the front is connected to the hard disc.

 SJ Research HDFS with circuit board removed

Removing the main circuit board from the HDFS shows:

• the top of the tape drive in the bottom left
• the power supply at the top left
• the Xebex 140786 interface for the hard disc in the middle front. I think this is a MFM/ST506 to SASI/SCSI board. I don't know the capacity of the drive on this HDFS and can't see a make/model number.

SJ Research HDFS circuit board (top) 

The HDFS main circuit board showing:

• in the bottom left the WD2793A controller for the tape drive
• to the left is the NEC D8237AC DMA controller
• at the back left is the CDP6402 UART
• to the right iare the 32 x TMS4164 DRAM for the 256KB cache RAM
• in the middle at the back is the SJ Research ROM marked "ZPROC ROM 130A"
• below the ROM is a Z80B CPU with 128K RAM (16 x M5K4164 DRAM) to the right
• in the top right is the Z80BSIO which also controls the Econet interface.
• in the bottom right is the SJ Reseach ROM marked "JPROC ROM 1.05"
• Below the ROm is the second Z80B CPU the 64KB RAM(8 x M5K4164 DRAM) to the right
• The white label at the front in marked "serial number 1043"

Here is a HiRes picture of the HDFS circuit board .

 SJ Research HDFS circuit board (bottom)

Note that there are a number of wire patchs on the bottom of the circuit board.