7 Mar
2023
7 Mar
'23
5:32 p.m.
On Mar 7, 2023, at 8:23 PM, Chuck Guzis via cctalk
<cctalk(a)classiccmp.org> wrote:
On 3/7/23 17:04, Zane Healy via cctalk wrote:
Was IBM the first for each of these?
I'm a bit puzzled by "6250 700'" because the reel size has no bearing on
the format. 10 inch reels (1200 feet) were by far the most common but occasionallly the
smaller 600 foot ones would be seen. and in rare cases (the infamous DEC TS05 comes to
mind) 600' was all that they could handle.
I’m working on a project, and I need to know the
age of various tape formats. For example when were 6250bpi 700’ 9-Track tapes or DC600A
cartridges introduced? Is there any good resource online that documents this? Wikipedia
is of some help, but the older you go, the spottier it is
Strictly speaking out of an orifice, I'd suggest that 9 track tapes in
NRZI and PE first came around with the IBM 2400 series tapes, GCR with
the 3400. Prior to the S/360, tape drives were largely 7 track
and used NRZI in
200, 556 and 800 bpi densities (IBM 700 series drives). Of course,
there are many outliers.
I added the 14-track CDC drives to the Wikipedia article a while ago. And I've been
learning a bit about the oddball 10 track 1/2 inch tapes used on the Electrologica X1
(and, apparently, on the Eliott (UK) as well). The X1 tape is unusual in that it's
somewhat like DECtape -- it supports random rewriting but with variable length blocks
limited by a size limit set at format time rather than a single fixed block size.
paul