The SJ Research MDFS (Modular Disc File Server) is widely regarded as the best Econet file server. Major features included its reliability, performance and flexibility. The MDFS could support up to 4 SCSI hard discs, 4 floppy discs, tape cartridge drive and 2 printers. SJ Research made matching expansion cases for floppy discs, hard discs and tape drives (see the MDFS brochures). However my MDFS (see first picture) has just 1 Watford Electronics SCSI disc attached. The disc is a Rodime 43MB RO3057S.
The MDFS configuration is:
The MDFS 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. The MDFS can support up to 80 logged-on users. In 1986 an MDFS with 20MB hard disc and tape streamer would have cost you £3,600 as an educational user.
Here is a brochure describing the SJ Research MDFS.
Here is a more detailed brochure MDFS The most advanced File Server for Econet
SJ Research MDFS with Watford SCSI Drive
SJ Research MDFS (front)
The picture shows the front of the MDFS. From the left to right are the controls and indicator LEDs: Release discs button, Discs Free LED, Utility Mode LED, Parallel printing LED, Serial Printing LED, No Clock LED, System Error LED, power LED, Online LED and the mode change lock.
SJ Research MDFS (back)
The picture shows the back of the MDFS. From the left to right: Fuse and power lead, Expansion box power connector, 2 BBC floppy disc drive power connectors, Econet socket, RS232 serial port, parallel printer port, 2 floppy disc drive connectors (Drives A&B and Drives C&D) and SCSI bus Interface.
SJ Research MDFS with cover off
The picture shows the MDFS with the top cover off, but is better seen in the next picture. Here is a HiRes picture of the inside of an MDFS.
SJ Research MDFS circuit board
SJ Research MDFS Stacked with Tape Drive (front)
This picture shows an SJ Research MDFS on top of the Tape Drive expansion.
SJ Research MDFS Stacked with Tape Drive (back)
The back of the SJ Research MDFS Tape Drive showing the power cable plugged into one of the MDFS auxillary power sockets and the SCSI cable plugged into the SCSI socket.
SJ Research MDFS Tape Drive (front)
The front of the SJ Research MDFS Tape Drive showing the slot the tape cartridge is inserted in.
SJ Research MDFS Tape Drive (back)
The back of the SJ Research MDFS Tape Drive showing the power cable, the SCSI ribbon cable and the serial number which is MDFS/532.
SJ Research MDFS Tape Drive (bottom)
SJ Research MDFS Tape Drive with top cover removed
Inside the SJ Research MDFS Tape Drive showing the 3M tape drive, and a lot of empty space.
SJ Research MDFS Tape Drive (right side)
I am not sure what the model the tape drive is, I think it uses a DC2120 tape cartridge but can't be certain. If so it would allow 2 MDFS Disc partitions (59MB) to beacked up onto a single DC2120 tape.