Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.atnf.csiro.au/pub/people/vlbi/s2/userman/S2-RT_ver3.0_133/tape.ps.Z Äàòà èçìåíåíèÿ: Mon Apr 7 20:15:59 1997 Äàòà èíäåêñèðîâàíèÿ: Mon Jun 28 03:30:45 2010 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï

Part
1:
/home/s2/doc/userman/working/txt/tape.txt
x
5. TAPE
5.1 Choice of Tape and Tape Speed
The following types of tape are approved for use in the S2. Other types of tape should be avoided.
Type
1. Scotch ® ST­120/SE­180 (20 micron) SVHS tape manufactured by 3M, now no longer in production.
This was available in North America as ST­120 and in Europe/Australia as SE­180 (about 5% longer
than ST­120).
2. Maxell ST­182/SE­260 (13 micron) SVHS tape. Also available as the very slightly shorter Maxell
ST­180. May be designated ``XR­S Black'' or ``Professional Broadcast Quality''. Note: These thin
tapes will not work in systems with AG2510 transports.
3. Ampex 289 ST­126/SE­180 (20 micron) SVHS tape. Some cassettes may be labeled ST­120 but are
actually the same length as the ST­126.
4. Fuji H471S ST­120/SE­180 (20 micron) SVHS tape. Available in North America as ST­120 and in
Europe/Australia as SE­180 (about 5% longer than ST­120).
The type of tape being used in the S2 must be specified using the tapetype console command or TAPETYPE_SET
RCL command. A default setting to use at bootup can be defined using the tapetype parameter in the system
defaults file (the defaults file is described in Section 4.2.7). The tape type is a one­digit code indicating one of
several approved varieties of tape as listed above and in Table 5­1. The tape type code is used by the S2 to
determine transport write­current levels, so technically it does not need to be set for playback but setting the
correct tape type is still recommended. For unlisted tape types it is possible to enter digits NNNMMM where
NNN is the write current for LP and MMM is the write current for SLP. These numbers must be determined
empirically and will typically be supplied by ISTS/SGL when a new tape type is approved for use in the interim
until the next offical software release (which will recognize the new type).
The ``fast'' S2 tape speed is LP (29 micron track pitch), and gives 4 hours 1 minute total recording time per
ST­126/SE­180 tape at a specified bit­error rate of less than 1 x 10 ­4 . Typical bit­error rates of around 1 x 10 ­5
can be expected. Operating the system at the SLP speed (20 micron track pitch) gives 50% longer recording
times, or 6 hours 2 minutes on ST­126/SE­180 tapes. There is no formal specification for SLP performance, however
typical bit­error rates of around 2 x 10 ­4 can be expected.
With Maxell ST­182/SE­260 ``thin'' tapes the SLP recording time is extended to 8 hours 41 minutes, and although
the thin tapes have not been formally specified, BER performance should be similar to thick tape. Note that thin
tapes (thickness less than 20 microns) do not work in AG2510 transports, but are fine in later transport models
such as the AG2520 and AG2530.
S2­RT User's Manual TAPE
5 ­ 1

Tape
Type Description Length
(meters)
Thick/
Thin LP Time SLP Time Notes
1 3M Scotch ST­120 246 thick 3h 50m 5h 45m discontinued
1 3M Scotch SE­180 258 thick 4h 01m 6h 02m discontinued
2 Maxell ST­182/SE­260 371 thin 5h 47m 8h 41m not for AG2510s
2 Maxell ST­180 367 thin 5h 43m 8h 35m not for AG2510s
3 Ampex 289 ST­120/ST­126/SE­180 258 thick 4h 01m 6h 02m
4 Fuji H471S ST­120 246 thick 3h 50m 5h 45m
4 Fuji H471S SE­180 258 thick 4h 01m 6h 02m
5.2 Tape Shipping and Storage
Tapes must be shipped and stored in closed containers. Canadian CSA tapes use a low­cost cardboard sleeve
designed to hold a set of 8 tapes, and a padded cardboard shipping container that holds 4 tape sets or 32 tapes
total. Whenever tapes are not in the transports they should always be placed in their containers. If no CSA or
equivalent tape containers are available standard VHS dust jackets may be used.
For maximum data integrity, tapes should be stored vertically in the fully rewound position. Tapes should be fully
rewound when shipped.
Tape Shipping Environment
The ideal shipping environment for tape is 19--22 degrees Celsius, at a relative humidity of 45% to 55%. Envi­
ronmental limits are to be determined.
Table 5­1: S2 Approved Tape Types
S2­RT User's Manual TAPE
5 ­ 2