Copying DEC VAX set up disks rx50, help - test-drb@ccmp.vtda.org

4 Mar 2007

...

Subject: Re: Copying DEC VAX set up disks rx50, help
   From: g-wright at att.net
   Date: Sun, 04 Mar 2007 20:08:17 +0000
     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>

-------------- Original message from "Ethan Dicks" <ethan.dicks at
gmail.com>: -------------- 

  On 3/3/07, g-wright at att.net wrote: 
  Hi, 

 I have a stack of the original VAX Disks (console and 
 set up , 5 1/4 RX50 ) The ones in front of me are 
 for a 8200 series. I would like to copy them but can't 
 get image disk to work. Is this possible or do I have to 
 use a VAX..   
 You should not have to use a VAX. There's nothing strange about the 
 low-level format for 8200 console disks (I have an 8200/8300 in my 
 basement, FWIW). 

  I have RT11 on a micro PDP-11 with a RX50 
 and I think my professional still works. But would really like to 
 get it on a better media for long term storage.   
 Sure. 

 > Image Disk reads it with out errors 
 > 0/0: 300k DD 10 sectors of 512 bytes - G1:9 G2:17 
 > 0/1: Single sided 
 > 0/0: Single Step 
 > 800 sectors (800 data, 0 compressed, 0 unaval) 
 > Read complete  

Heres is where I believe I missed the problem.  The disks are not full
using Anadisk on the floppy, data ends at  cylinder 28 and is
blank to the end.  Anadisk can scan the whole disk with out errors.
with 800 data and no compressed some thing is wrong.  If I understand 
Image disk correctly.
I moved to another Image Disk machine (I have 6 now) and its seems to 
work fine. Although I believe the proof will be by trying them.  The 
new readings are  (800 sectors, 472 data, 328 compressed, 0 Unavail)
and the Write works with out errors.  The original  IMD file size was 
400k the new one is much smaller.  I have writen these out on both 
DD and HD media.  both bulk erased first.

HD media will have an increased likelyhood of errors as its the wrong
media for tha data rate.

...

 So far, so good... 

  Trying to write and it has errors from the get
go. 
 0/0: 300k 10 sectors of 512 bytes 
 :format error <0> overun 
 :write error <2> no sector 
 and on ............................. 

 written on a PC with 1.2 HD drive 
 Tried on another 1.2 and on a 360k drive 
 all capable of SD . 

 I tried both HD and DD disks . all bulk erased first.   
 Hmm... Others on the list can chime in with their floppy expertise, 
 but from the way you are describing what you've tried, it doesn't 
 sound as if you have a clear picture of the media in front of you.  

Boy did you read that one right  Thank you Ethan ..............   This did  help
move me along.

> 
> RX50 disks are single-sided (as mentioned by imagedisk in your read 
> example, above), 80-track, ten 512 byte-sectors per track for a total 
> of 400Kbytes. Your 360K drive can _not_ write RX50 disks (among other 
> issues, it's a 40-track drive). 
> 
> If you've verified that your 1.2MB drive works as a PC drive, then, 
> presuming you have the right media, you shouldn't have any hardware 
> issues writing RX50 images. Media is where I get a little fuzzy on 
> the details. I've personally only ever written RX50 images to RX50 
> media. I've never tried to recycle PC floppies, so I'm not sure what 
> the best choice is. I do seem to recall that what you want should 
> *not* have hub reinforcement rings, as they can cause alignment 
> problems in real RX50 drives.  
The Problem os If the 1.2mb drive works your're cooked as the format is 
not 1.2mb or even close.  You would be testing for the worng thing.

...
 > If you can score a Teac FD55GFR drive, it can be
strapped up to be a 
> _real_ RX33 or strapped to behave "normally" on a PC FC controller. 
> The strapping has to do with motor on and select lines, not data, BTW. 
> I mention the FD55GFR because it was the 5.25" drive DEC shipped 
> after they moved on from the RX50, so you can be sure that you aren't 
> having hardware compatibility issues (plus, it's all-around good, 
> solid 5.25" drive).  
Either strapping the FD55GFR for 360rpm only and 250kbs data rate only
or better yet use a FD55E.

...
 I did try this and it is the controller that causes the
problem. no to sure
why ???

I have been re-reading all of my disks with image disk and have found
that many of my original disks worked fine but the copies I made on the 
original hardware had bad tracks.  So now I'm re-writing everything and
trying it in the original machine if possible.  The machine here that did not
work was my main machine for 22disk, anadisk and teledisk. But it has a 
secondary  controller (compaticard 4) with 4 more external drives.  
FYI: IF the original hardware has an RX50 drive.. thats your problem as 
they tended to have speed and alignment problems galore.  when the RX50 
drive is questionable (all are untill proven working!!!) I sub in a 
pair of FD55E or suitably (nonDEC jumpering) jumpered pair of FD55GFR 
with a hacked up cable and pull the RX50.

Since I have a collection of Qbus VAXen and Qbus PDP-11s it's far easier
to rely on the RQDX3 and RX33 drives as they do RX50 just fine and do 
not incur the RX50 relability issues.  Also the RX50 is just plain LOUD.

Allison

...
 The most trouble free set up so far is a  Adaptec
AHA-1542cp  SCSI
controller with floppy.  I now have 4 PC's with this card and have not seen 
any problems with single density or in this case odd formats.  These are the
ISA version with a HD SCSI connector on the back. Some of the other
version of the card can't do Single density.

 In your case, I'd run some read/write/verify tests with your 1.2MB 
 drive and PC-compatible floppies and if they show any marginal 
 problems, try cleaning the heads. You can clean the heads in any 
 case, but it might be nice to have a "before" picture to compare 
 post-cleaning performance. If you can locate some real RX50 media, 
 try writing to those. They aren't "magical", but they are 
 pre-formatted for 10 sectors-per-track (MS-DOS uses 9 sectors for 360K 
 disks and 17 sectors for 1.2MB disks, if you didn't remember). As 
 with the RX01s, most DEC equipment can *not* lay down the RX50 
 low-level format, the Rainbow being the most notable exception. A PC 
 _can_ format an RX50, but you'll need some 3rd-party tool to do that - 
 DOS can't by itself. 

 I'm sure others will be able to chime in with various informed opinions. 

 -ethan 

 P.S. - just found this old doc on the state of RX50s and various 
 versions of DOS and tools for DOS... 
 http://www.classiccmp.org/rainbow/files/rx50faq.doc Dunno what OS you 
 are using to write your disks, but perhaps some info in this FAQ will 
 shed some light.  
I have a good friend that has almost every  VAX and PDD machine made
so He is going to test these.  

After these disks get tested,  I will post a follow-up.  

Thank, Jerry

Jerry Wright
g-wright at att.net 