Burnable, patched Microvax-2000 SCSI-boot EPROM images?

Mike Katz bitwiz at 12bitsbest.com
Sun Sep 26 12:34:24 CDT 2021


I just purchased an RK05 Controller for my PDP-8/E, does this emulator 
work to emulate RK05 packs?  If it does then maybe I can use it as mass 
storage until i can find an RK05 (or Plessey or Diablo clones) .

Thanks...

On 9/24/2021 3:19 PM, David Gesswein via cctalk wrote:
> On Tue, Sep 21, 2021 at 12:15:12PM -0400, Paul Koning wrote:
>>> On Sep 21, 2021, at 12:00 PM, Jonathan Stone via cctalk <cctalk at classiccmp.org> wrote:
>>>
>>> The RD53s in both Microvax 2000s are dead. I'm reluctant to buy more 30+ year old rotating media.
>>> If I'm going to buy a disk emulator, I'd much prefer SCSI to MFM, for the obvious performance reasons.
>> Emulators presumably act, performance wise, like SSDs.  Given that, an MFM emulator will significantly outperform a SCSI hard drive since it has no seek delays.
>>
>> David Gesswein's MFM emulator works impressively well and is inexpensive, too.
>>
> The MFM emulator can't transfer data faster than the 5 Mbit/second,
> 625k Byte/sec of the ST-506 standard.
>
> Seek time isn't zero due to overhead in moving the data in the Beaglebone
> to where the PRU processors can access it. Think its around 0.6ms/head. An
> entire cylinder is transfered on each seek. Additional time if cylinder
> was written to. Each track written needs to be moved also. Most ST-506
> drives are slower. I'm faster than average seek for RD54 but it wins for
> single track seek at 4ms with 15 heads.
>



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