shadoooo said > Hello, > I'm a decent collector of big iron, aka mini computers, mainly DEC and DG. > I'm often facing common problems with storage devices, magnetic discs and > tapes are a little prone to give headaches after years, and replacement > drives/media in case of a severe failure are unobtainable. > In some cases, the ability to make a dump of the media, also without a > running computer is very important. > > Whence the idea: realize an universal device, with several input/output > interfaces, which could be used both as storage emulator, to run a computer > without real storage, and as controller emulator, to read/write a media > without a running computer. > To reduce costs as much as possible, and to allow the better compatibility, > the main board shall host enough electrical interfaces to support a large > number of disc standard interfaces, ideally by exchanging only a personality > adapter for each specific interface, i.e. connectors and few components.> > There are several orders of problems: > - electrical signals, number and type (most disk employ 5V TTL or 3.3V TTL, > some interfaces use differential mode for some faster signals?) > - logical implementation: several electrical signals are used for a specific > interface. These must be handled with correct timings > - software implementation: the universal device shall be able to switch > between interface modes and be controlled by a remote PC > > I suppose the only way to obtain this is to employ an FPGA for logic > implementation of the interface, and a microprocessor running Linux to handle > software management, data interchange to external (via Ethernet). This means > a Xilinx Zynq module for instance. > I know there are several ready devices based on cheaper microcontrollers, but > I'm sure these can't support fast and tight timing required by hard disk > interfaces (SMD-E runs at 24MHz). > > The main board should include a large enough array of bidirectional > transceivers, possibly with variable voltage, to support as much interfaces > as possible, namely at least Shugart floppy, ST506 MFM/RLL, ESDI, SMD, IDE, > SCSI1, DEC DSSI, DEC RX01/02, DG6030, and so on, to give a starting point. > The common factor determining what kind of disc interface can be support on > hardware side is obviously the type of transceiver employed, for instance a > SATA would require a differential serial channel, which could not be > available. > But most old electronic is based on TTL/CMOS 5V logic, so a large variety of > computer generations should be doable. > > For the first phase, I would ask you to contribute with a list of interfaces > which could be interesting to emulate, specially if these are similar to one > from my list. > I please submitters to send me by email or by web link when possible, > detailed documentation about the interface they propose, so I can check if it > could be doable and what kind of electrical signals are needed. > Also detailed information about interfaced I listed is appreciated, as could > give some detail I'm missing.
The Diablo / Pertec interface was a popular industry standard. Here's a product (no connection) that implements it https://www.arraid.com/data-storage-products/product/aem-5c.html It would be great if there were open source or cheaper devices, maybe there are, I guess the Unibone can do this? (I don't have one yet) (btw I never actually subscribed to cctech but somehow my cctalk ones get echoed over there)
