Planning Considerations for I I I 2314/ I I 2319 3330 3340 I 3350
r I , , Maximum number of files , 3500 3400 3400 , 3400 I that can be contained on , I , the disk I I .. I I I Maximum minidisk size I 203 246 348 , 115 , (in cylinders) I (model 35) , 1 , 682 , I , (model 70) , .. +-- I I Number of 800-byte blocks I 150 266 96 I 570 , per cylinder I I .. I , Maximum data extent records ""'-',-'...Iv , 12,848,000 bytes
L
Figure 3. CMS Disk File Statistics
IDENTIFYING DISK FILES CMS commands are provided to list the identifications of files on eMS and non-CMS formatted disks and minidisks. The LISTFILE command. lists
the entries in the master file directory for CMS disks; the LISTDS command lists the entries in the VTOC (volume table of contents) for as
and DOS disks, or for listing data spaces on VSAM volumes. eMS Tape Support
Each CMS machine can support up to four magnetic tape units at virtual
addresses 181, 182, 183, and 184. They may be 2401, 2402, 2403, 2415,
2420, 3410/3411, or 3420 drives, or a mixture of tape drives.
Three tape-handling commands (ASSGN, FILEDEF, and TAPE) allow you to
specify the modeset of the tape: track (7-track or 9-track), density,
and, for 7-track tape only, the tape recording technique (odd or even
parity, converter on or off, and translator on or off) If you do not specify the modeset for a 7-track tape, CMS issues a
modeset indicating 7-track, 800 bpi (bits per inch), odd parity,
converter on, and translate off. If the tape is 9-track, the density is
assumed to be 1600 bpi (or whatever bpi the tape drive was last set at)
for dual density drives; for single density drives, whatever bpi the
drive is (800, 1600, or 6250 bpi) is assumed.
As an alternative to specifying mode in each command that uses the
tape (for example, FILEDEF), you can issue a CMS TAPE command that sets
the mode for the tape and stays in effect until reissued. You must do
this if one of your programs is to use tapes in other than the default
mode. With one exception, eMS commands permit only unlabeled tapes to be
read or written. However, the eMS TAPPDS command can read standard as
tape labels. Your programs executing under eMS must use unlabeled tapes
or provide code to create and read their own labels as data records. Part 1. Planning for System Generation 27
Planning Considerations for CMS Multivolume tape files are not supported by CMS. These restrictions only apply when you run CMS. DOS and as
systems running in virtual machines can continue to read and write tapes
with standard labels, non-standard labels, and no labels on single and
multireel tape files.
The VM/370 operator must attach tapes to your CMS virtual machine
before any tape operation can take place.
For information about tape handling in the CMS/DOS environment, see
"Planning Considerations for CMS/DOS." eMS Unit Record Support CMS supports one virtual card reader at virtual address OOC, one virtual
card punch at virtual address OOD, and one virtual printer at virtual are spcolea. does not support real or dedicated unit record devices, nor does it support a
virtual 2520 Card Punch. Figure 2 lists the devices supported as
virtual devices by CMS. CARD READER
The READCARD command reads data records from the spooled card reader to
a CMS disk. Input records of 151 or fewer characters are accepted.
Column binary data is not acceptable. Your card decks must be read into
the virtual reader before a READCARD command can be issued. Do one of
the following: Place a card deck, containing only one file, in a real card reader
and have CP read it. The card images are placed on a spool file in
the specified virtual machine's virtual card reader. If you are not
logged on when data is spooled to your virtual card reader, the deck
remains in your virtual card reader until you log on and issue the
READCARD command. Transfer records from your virtual card punch or printer to a virtual
card reader (your own or that of another virtual machine).
For more information on reading files from the CMS card reader, see
the VML170 CARD PUNCH The eMS PUNCH command causes the specified file to be punched to the
spooled card punch. Records up to 80 characters long are accepted. Shorter records are padded to 80 characters with blanks filled in to the
right. The following are not supported: Punch stacker select Punch feed read 3525 Multiline Card Print feature 28 IBM VM/310 Planning and System Generation Guide
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