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

[Paul Sture]

In article <QMHlFQS6wZyr at eisner.encompasserve.org>,
 koehler at eisner.nospam.encompasserve.org (Bob Koehler) wrote:

> In article <k4v41o$bte$1 at Iltempo.Update.UU.SE>, Johnny Billquist 
> <bqt at softjar.se> writes:
> > 
> > Even by asking that question, you reveal that you have not used the 
> > TU58... :-)
> > Slower than DECtape? Hell yes. DECtape flies compared to it. DEC did 
> > call the TU58 for DECtape II, but that really an abuse of the DECtape name.
> 
>    You got that backwards.  I've done a standalone backup boot off TU58,
>    later followed by an OS upgrade.
> 
>    I've seen, but not used, DECtape.  I had no idea how fast it actually
>    moved the small amount of data it held.

I once met someone who had used DECtapes and he had been very impressed 
by them in their day, but he was at least 20 years my senior.  IIRC he 
described some mechanism where they skipped alternate blocks when 
reading or writing so that the tape speed could be higher, and those 
skipped blocks were used when the tape was travelling in the opposite 
direction.

The Wiki entry unfortunately doesn't have any dates, but does claim that 
they were a lot more reliable than disks of the day:

http://en.wikipedia.org/wiki/DECtape#Technical_details

"Upon its introduction, DECtape was considered a major improvement over 
hand-loaded paper tapes, which could not be used to support swap files 
essential for practical timesharing. 

...

The hard disk system (when it was working) was considered a "temporary" 
file storage device used for speed, not to be trusted to hold files for 
long-term storage. Computer users would keep their own personal work 
files on DECtapes, as well as software to be shared with others."

>    I always suspected that DECtape is what the first initial in TECO
>    refers to.  8-)

The official title of the TECO User's Guide says "Text Editor and 
Corrector", but it wouldn't be the first time an official version of an 
acronym differs from the unofficial original. ;-)

-- 
Paul Sture