SCSI Tape Emulator

Josh Dersch derschjo at
Mon Oct 10 20:45:16 CDT 2016

On 10/10/16 6:19 PM, Chris Hanson wrote:

> On Oct 10, 2016, at 6:11 PM, Josh Dersch <derschjo at> wrote:
>>> On 10/10/16 5:40 PM, Charles Anthony wrote:
>>> On Mon, Oct 10, 2016 at 4:49 PM, Rich Alderson <
>>> RichA at> wrote:
>>>> From: Charles Anthony
>>>> Sent: Monday, October 10, 2016 12:53 PM
>>>> Correction:  .tap format uses 4 byte counters, in little-endian order.
>>>> Order is not relevant for the EOF tape marks, of course, since they're
>>>> 4 bytes of 0.
>>> Stupid memory of mine. Sigh.  Anyway, IIUC, the SCSI2SD is like $70; the
>>> firmware appears to be closed, but I wonder if an NDA with them would allow
>>> adding tape emulation capability to their code base? (Given that I have no
>>> knowledge of how SCSI2D works inside, I may be vastly underestimating the
>>> scope of the project.)
>>> -- Charles
>> The SCSI2SD firmware (and hardware) are open source, see the "Files" section of the scsi2sd site for the git repo information.
>> Additionally, the guy behind the project is very receptive to feature requests and bug reports...
> I was going to point this out as well.
> My only misgiving would be whether SCSI2SD prior to v6 is powerful or fast enough for any particular use, not whether sufficient resources are available to hack it.

For *any* particular use?  No -- I wouldn't put it it to use in a 
datacenter :).  I have, however, used it on a wide variety of machines.  
Right now I have them in a Sun 3/60, a VAX-11/750, a VaxStation 3540, an 
AT&T 3B2/600 and a Symbolics XL1200 where they work flawlessly.  There 
are certainly vintage machines where the SCSI2SD V4 would be noticeably 
slower than a real drive, but many vintage machines are simply not fast 
enough to come close to the peak throughput of the SCSI2SD.

- Josh

>    -- Chris
>    -- who still needs a JTAG cable to reprogram the boot loader on his bricked SCSI2SD

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