[Simh] DEC floppy disk interleave questions

[Armistead, Jason BIS]

Dying RFxx disks might be due to failure of FLASH memory in the controllers (either onboard the CPU or external chips).  The charge in the memory cells in FLASH memory chips doesn't last forever, and slowly bleeds away.  Early devices could fail after 10 years.  Newer FLASH parts are better, but the lifetime is not infinite like it was with PROMs/EPROMs.

The folks at CMU and LSI Corp wrote a good article about this:

http://users.ece.cmu.edu/~omutlu/pub/flash-memory-data-retention_hpca15.pdf

And to Alan's floppy archiving plans - Just remember to regularly "refresh" your CD collection.  Those CD-R disks don't last forever either!  If it was me, I'd be creating at least two copies.

Cheers
Jason

-----Original Message-----
From: Simh [mailto:simh-bounces at trailing-edge.com] On Behalf Of Hans-Ulrich Hölscher
Sent: Thursday, 16 July 2015 9:16 AM
To: simh at trailing-edge.com
Subject: [Simh] DEC floppy disk interleave questions

>
>  > if you want to image your disks and floppies for use with simh,  > 
> there's an easy way to do it.  All you need is a (Micro-)VAX  > having 
> the appropriate drive(s) running VMS.
>  > MOUNT/FOREIGN
>  > COPY/LOG  yourimagename.img
>  > DISMOUNT
>  > Don't worry about the error message at the end of the COPY process  
> > - that's normal, just that copy discovers the end of media.
>  > You get an image containing all the blocks of your device in  > 
> logical order - VMS will take care of the device details.
>
> That sounds like the really easy way to do it.   Does it copy
> track 0 of RX01/02 floppies?

Every bit that is readable normally from VMS, hiding only strange sector orders and bad block information.
Images from bootable devices are bootable within simh (as long as there's a suitable bootable simh device)

>
> I finally got a MicroVAX 3300 up and running again.   Most of
> my RF3x drives seem to have died while in storage.  Now I have to see 
> if any of the RX02 drives will still work.

So are my RF3xs :-((
My DSSI-VAXen run on HSD coupled RZ disks in BA350 boxes now.

>
>  > Will you make your images available?
>
> Absolutely!   I'm still working on the 9-track tapes, after a
> several-week pause due to my Alpha XP1000 dying and me taking time out 
> for a couple of all-weekend endurance races (24 Hours of LeMons -- the 
> fruit, not the town in France).
>
> I plan to put all my DEC media images on CDs so I can easily
> make copies.   Each tape/floppy image will be accompanied by a
> text file with the label and other information, and a .JPG photo
> of the media and label.   I've done about 300 tapes so far, of
> which 82 are DEC.   I have another 300 or so to do.   I should
> be done in a couple of months.
>

I'm very keen on your software pool, many thanks for preserving it!

As you probably know I'm mainly after old VMS software (everything pre VMS V5)
 

Regards

Ulli




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