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High-performance
backup for VM data. |
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| XDR is designed to speed up the most
commonly used functions of the DDR utility supplied by IBM with VM. The
basic functions are to COPY disks, DUMP data to tape, and RESTORE data back
to disk. XDR is syntax compatible with the DDR utility; it supports the same
basic control statements which are either entered interactively or provided
through a CMS file. Tapes created by XDR can subsequently be used by DDR,
and vice versa. The special header records found in a tape file are
compatible between the two utilities. Tape volume handling (positioning,
end-of-volume processing) is also compatible. Data written by XDR to disk
will be the same as if DDR had operated. |
| Current maintenance for XDR is "XDR122G",
a self-contained REXX exec that brings any version of XDR Release 1.2 to the
most recent maintenance level. |
| Support for Year 2000 related issues
is included when the "XDR122G" maintenance file is applied. |
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| PERFORMANCE
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| XDR operates from 2 to 4 times faster
than DDR. This is achieved by using sophisticated I/O techniques to read and
write data. XDR can operate on up to a cylinder's worth of data at-a-time,
while DDR processes only one track's worth per I/O request. Disk latency
times are reduced; improved synchronization between disk and tape devices
also results from coordinated I/O. In addition, XDR will attempt to perform
simultaneous reading, writing, and compacting of data. |
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 | DUMP and RESTORE operates 2 to 3
times faster. |
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| COPY operates up to 4 times faster. |
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| VTIME for Compact reduced 30 to
50%. |
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| ESA and XA-exploitation mode
available. |
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| Input and output operations are
simultaneous when possible. CPU overlap achieved when Compacting. |
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| Main memory use and channel program
size are controlled by options. |
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| ECKD Storage Control optimization
available. |
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| FEATURES
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| XDR supports most DDR options at
high-speed. It can, for example, DUMP all or selected portions of a disk,
RESTORE subset cylinders, optionally REORDER the output location, and
position input and output tape units as DDR does. XDR can create the backup
tapes used for disaster-recovery purposes. |
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| A "file-level-restore" ability is
provided by XDR. From either an XDR or DDR dump tape, a single file, many,
or all CMS files can be restored to disk. A new "CMSREST" control statement
has been added for this feature. The output disk need not be the same as the
original input device type, providing a level of device independence not
previously available with DDR. |
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| Standard IBM tape labels are
supported through the use of either the CMS TAPESL facility or through OS
simulation calls. Erroneous tape mounts can be prevented. VM tape managers
are activated when OS simulation is used. |
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| COPY, RESTORE, DUMP, INPUT, OUTPUT,
PROMPTS, SYSPRINT control statements supported. |
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| Operates with a cylinder level
granularity. |
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| Input and output tapes positioned
via SKIP and REWIND/LEAVE/UNLOAD options. |
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| File level restore ability for CMS
minidisks. |
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| Device independent restore for CMS
minidisks. |
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| Tape cartridge display can indicate
volser to mount. |
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| Standard tape label support is
available. |
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| Works with VM tape management
systems. |
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| Bypass input I/O errors during
DUMPs or RESTOREs. |
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| Unique options to XDR: IOLIMIT,
OVERLAP, DORIG, OLDDATE, TYPE, PREERASE, BEXTENT, CMST, SL, SLOS, EMSG,
ESKIP, CCOMPACT, BLK64K, DISPL# options. |
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| NUCLEUS option is not supported. |
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| Stand-alone operation available
through DDR. |
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| REQUIREMENTS
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| XDR runs under: |
| VM/SP Release 3,4,5, and 6. |
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| VM/HPO Release 4,5, and 6. |
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| VM/XA/SP Release 1 and 2. |
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| VM/ESA 1.1.0, 1.1.1, 1,2.1, 1.2.2,
2.1, 2.2, 2.3. |
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| Installation is a TAPE LOAD of files
from an installation tape, and can be completed in under 15 minutes. No
modifications to CMS or CP are necessary. |
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