At 09:19 AM 12/3/98 -0500, Jeff Kell wrote:
>Jeff Woods wrote:
>> At 12:20 AM 12/3/98 -0000, Andy Leates wrote:
>> >Does anyone know how to label a DLT Tape, or any other removable
>> media for that matter?
>>
>> :FILE mytape;DEV=tape;LABEL=dlt123,ANS,12/25/98
>
>And what happens to said labels after 12/31/1999 ?

The FILE command and FOPEN() and HPFOPEN() intrinsics all now support
either 2 or 4 digit years for the expiration date, according to
http://jazz.external.hp.com/papers/Communicator/5.5/exp4/cmy2k.html

I notice there the following curiosity, however:

---LaserROM-excerpt-begins----------------------

Two-Digit Years Interpretation

One of the ways for handling two-digit year input is to interpret the years
in the method called fixed window method. In this method, the two-digit
years map as follows:

00 .. 49 maps to 2000 .. 2049
50 .. 99 maps to 1950 .. 1999

For example, both of the following STREAM commands will schedule the
JOBFILE as January 21, 2001:

:STREAM JOBFILE;DATE=01/21/2001
:STREAM JOBFILE;DATE=01/21/01

Intrinsics
The CALENDAR intrinsic and CALENDAR date representation format are widely
used in MPE/iX. There are many other intrinsics that accept or return dates
in calendar format. The following discussion clarifies the interpretation
of calendar format year value.

CALENDAR Intrinsic

The CALENDAR intrinsic returns the CALENDAR date, including the day of year
and the year of century. The existing CALENDAR intrinsic documentation
refers to the year as "year of century." This should be interpreted as
"year since 1900."

The new definition of the CALENDAR intrinsic is as follows:

Syntax

U16
date:=CALENDAR;

where date is a 16-bit unsigned integer (assigned functional return).

This returns the CALENDAR date in the following format:

Bits Value/Meaning

7:9  day of year
0:7  year since 1900

Description

For the year 2000, the CALENDAR intrinsic will return the year as 100, for
2001 as 101, and so on. With this current interpretation, CALENDAR format
can handle years through 2027.

All intrinsics accepting or returning dates in CALENDAR format will behave
the same way as the CALENDAR intrinsic.

NOTE: If your application uses the CALENDAR intrinsic or CALENDAR format,
it may be required to verify the source for conformance to the above
interpretation.

---LaserROM-excerpt-ends------------------------

Note that the CALENDAR() intrinsic only handles dates through 2027, but
two-digit dates from 28 to 49 are interpreted as 2028 to 2049 respectively.
 Thus those dates can't be handled by the CALENDAR() intrinsic.  However,
many other functions presently appear to rely on and/or accept or return
dates as parameters in CALENDAR format.  Therefore, I don't know how well
dates beyond 2027 are going to be handled.  Personally, I expect problems
with applications trying to use such dates in MPE interaction, including
labeled tape expiration dates.

FWIW, Tivoli's RoadRunner and Tapes+ handle dates to 2027 and use the fixed
window method as explained above, except the break is between 27 and 28
rather than 49 and 50.  In other words, those applications treat two digit
years from 00 to 27 as 2000 to 2027 and 28 to 99 as 1928 to 1999.
--
Jeff Woods
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