[Info-vax] TK50 - this is annoying...

[Johnny Billquist]

On 2012-10-08 14:19, Stephen Hoffman wrote:
> On 2012-10-08 11:28:08 +0000, Roßert G. Schaffrath said:
>
>> On 10/7/2012 9:38 PM, Arne Vajhøj wrote:
>>> On 10/5/2012 6:48 PM, Lee Gleason wrote:
>
>>>
>>> Just having tried booting from one of those is enough to sympathize
>>> with that action.
>>
>> As bad as TK50's were, they were a definite improvement over the TU58.
>> I recall much lost time waiting for an 11/730 bootstrapping microcode
>> from one of those.
>
> Correct.  The immediate predecessor of the TK50 was not, however, the
> TU58.  It was arguably either the RX50 floppy, or the 9-track magtape.

I'd probably argue the TK25...

But if we continue moving back, then sure. 9-track more like the 
predecessor.
RX50 floppies? Not really, even though they were both used for distros. 
RX50 was, however, very contemporary with TK50.

And RX50 floppies runs back to RX02 and RX01. In some way, you might be 
able to argue that RK07,RK06,RL02,RL01,RK05,RK03 are the predecessors in 
that vein. And in reality, TU58 are also in this group, and not really 
in the tape group, name and media not withstanding.

TU58 - The worlds slowest disk? :-)

> As stinky as the TK50 technology is now, it was better than what went
> before it.  Both for DEC to create the installation media, for DEC to
> support (and then have to replace disks in) the installation media, and
> for the end-user to not have to swap the media nearly as often or to
> call up DEC to get replacement media.
>
> Booting a TK50 was a marvelous experience, back then.

Not really. It was good, in that you normally didn't have to have a 
whole bunch of them, but they were slow as molass back then too.
Especially when you compared to a TU78 or something similar.

Actually, compared to any other tapes I can think of. (TU58 not counted.)

Not to mention that they often broke even back then. I remember when I 
worked at DEC in the mid 80s. We have a VAX-11/750, with a TUK50, which 
we used on a semi-regular basis. That drive was sitting with the cover 
permanently off, and as few screws as we could get away with, so that it 
was quick to pick it apart whenever it messed up, which happened regularly.

> It was fast (for its time), and you didn't have to babysit five boxes of
> distro floppies, or a dozen magtapes and where one or two would
> seemingly inevitably cause the TU80 to start "maytagging".   Ok, so the
> hammerhead leader broke off from time to time, or MUA4224: showed up. It
> wasn't like floppies or magtape worked perfectly back then, though.

True that it was nice to have just one tape for the whole installation. 
However, in addition to the leader pickup breaking off, you occasionally 
had it just jump off the arm that was holding it in place when no tape 
was loaded. And you occasionally had to pick tapes out by hand, and you 
had to clean the heads pretty often.

Yes, 9-track was not always perfect either, but they were damn reliable 
even so. TU80 was mostly a drag because it only do 1600 bpi. The TU81 is 
nicer. And still reliable (yes, I have one or two still around).
The TU77 and TU78 was even better, but they did require more power, as 
well as Massbus (but I have a few of those still around as well).

	Johnny