How common are M7555 RQDX3 Controllers ???

[Gerardcjat]

I mean :

WHO is using it : - with Floppies,

BUT more important,

WITH MFM HARD DISK(s) ???

Said another way, **IF** I go this way, will I be alone ??

 

[Lou - N2MIY]

Gerard,

It's extremely common and many folks with qbus systems will eventually get an RQDX3. I use them and know them well. They were used in both pdp-11 and microvax systems. One annoyance had been that there were certain other manufacturer's drives that were selected by dec to be the drives to be officially supported by dec. They labeled them as RDxx. The XXDP formatting routines were preset with the drive geometries for these RD series drives, and the surviving copies of those routines did not offer any menus for directly inputting different geometries.

I have studied the diagnostic listings and prepared a paper describing how to patch the ZRQCH0 disgnostic to low level format any geometry of disk (not just RDxx). That effort I started this thread for : http://www.vintage-computer.com/vcf...H0-to-use-any-geometry-MFM-hard-disk-on-RQDX3

Lou

 

[Gerardcjat]

Lou,
I remember this post.
You may, if you wish, send me your form / work, I will be glad to receive it, but be aware that ** months ** will pass before I can comment on this, as so far I am **still ** in the process of fixing the Power Supply of my only PDP 11/23.
In fact, I received the needed tanks capacitors YESTERDAY !!
( The parcel got lost !! )
Gerard