[Info-vax] search for SDI and SMD disks (in europe)

[Hans Vlems]

On 31 mei, 08:49, Johnny Billquist <b... at softjar.se> wrote:
> On 2011-05-30 20.40, Richard B. Gilbert wrote:
>
>
>
>
>
> > On 5/30/2011 4:06 AM, Johnny Billquist wrote:
> >> On 2011-05-30 00.32, Hans Vlems wrote:
> >>> On 28 mei, 14:01, shadoooo<shado... at gmail.com> wrote:
> >>>> Hello.
> >>>> To restore a couple of old machines I'm searching for fixed and/or
> >>>> removable disks.
> >>>> For one machine I would need an SMD disk or cartridge drive.
> >>>> For the other machine, I need an SDI disk unit.
> >>>> If anybody has some to sell a reasonable price, please let me know.
> >>>> Thanks
> >>>> Andrea
>
> >>> Andrea,
> >>> an SDI disk unit means an RA drive, right?
> >>> Not that I have one, just curious if an RA90 or RA72 may still be
> >>> found !
> >>> Hans
>
> >> I guess this is not the right time to talk about the 50+ RA90 drives we
> >> tossed about five years ago...
>
> >> Johnny
>
> > RA series drives belong in a museum! They were pretty good disks for
> > their day but that day is LONG GONE! They were power hogs, 35 ampere
> > starting surge and something like seven amperes steady state for the RA-81.
>
> You make a big mistake when you group all RA-disks together like that.
> RA8x disks are nothing like RA9x disks, which again nothing like the
> RA7x disks. RA7x disks are just plain 5 1/4" full height disks. Draws
> very little power, takes no more space than contemporary SCSI disks (of
> the early 90s), and are no problems at all on modern machines.
>
>         Johnny- Tekst uit oorspronkelijk bericht niet weergeven -
>
> - Tekst uit oorspronkelijk bericht weergeven -

That sums it up quite nicely!
I never had any problems with RA81 disks, they failed just about as
often as
other disks did at the time (1980-1990). The company I worked for had
more than 30
RA81 disks attached to VAXes and PDP-11's (11/44, 11/84 IIRC). They
needed some
preventive maintenance though, like replacing the copper spring clip
on the spindle.
Some of the RA81's were still in use in 2002.
I've never seen an RA90 or RA92 fail, can't remember what happened
with RA7x drives.
Hans