are not used

DESCRIPTION The cylinder and the track address

Bits 4-7 are not used

0:

STANDARD DASD FILE LABEL, FORMAT 4 This format is used to describe the Volume Table

of Contents and is alWO)lS the first label in the

nNUrnber

of Alternate Tracks vrOC. There must be one and only one of these r:VTOC Indicators Format 4 file labels per volume.

I

I~C:'~ Extents nala

3 4 5 6 U

Device Constants 9

Last

Next

11~lij

Key ^{Fonnat 1}Active

;r

h~Ln ^{Oil •} ^DeviceSize

_4!

-

ⁱⁱⁱ ^~

^Ii

^f:l ^ill ^i? ^l!il

^!( ^~

^_!li ^;:: ^I~

&:tent Sequence Number Format ID---.l LAvaiJable File Label Records.

F.·.~~·.

IVSAM indicators lOA lOB OC Extent

15

Y~'8l}!:Jrtamp ¹¹

14

VSAM

~~

^'1;~ ^Reserved ^Lower^Upper ^Reserved

Timestamp _~ucompatibility) Limit limit

l~ ::\ ¹⁰ ^{-0 ...} ^~ _~~

!fl

⁰⁰~

:::~ !!!:2 §

~ NAME AND LENGTH DESCRIPTION FIELD NAME AND LENGTH DESCRIPTION

KEY FIELD Each byte of this field contains the Hex 4 bytes alternate for a bad track.

44 bytes,binary code 04 in order to provide a unique key. 6 N UMBER OF ALTER- Contains the number of alternate tracks

FORMAT ID 4: Format 4. NATE TRACKS available.

1 byte, EBCDIC numeric 2 bytes,binary

LAST ACTIVE FORMAT 1 Contains the addres.{in the farm CCHHR) 7

vroc

INDICATORS Bit 0, if on indicates no DADSM(Format 5)

5 bytes of the last active Format 1 file label. It label,or DADSM label does not reflect

is used to stop a search on a file name. true status of volume.

(OS/VS only) Bits 1,2 not used.

NEXT AVAILABLE Contains the address(in the form CCHH) Bit 3, if on indicates a stacked pack for the ALTERNATE TRACK of the next track to be assigned 'as an 1401/1440/1460 Emulator Program.

Bits 4-7 are not used.

\'-... '~

STANDARD DASD FILE LABEL, FORMAT 4 ( •••• COnt'd)

FIELD . NAME AND LENGTH DESCRIPTION

8A NUMBER OF EXTENTS Contains the hexadecimal constant Ol,to I byte indicate one extent in the vrOC.

8B RESERVED Reserved

2 bytes

DEVICE CONSTANTS This field contains constants describing the device on which the volume was mounted when the vroc was created. The following describes each of the subfields:

14 bytes

Device Size:

T:Track length:

;;::;

Record Overhead:

three

Flag:

(4 bytes)-The number of cylinders(CC) and tracks per cyl-inder(HH).

(2 bytes)-The number of available bytes on a track exclusive of home address and record zero. (record zero is assumed to be a nonkeyed record with an eight bytes data field) (3 bytes)-The number of bytes required for gaps, check bits, and count field for each record. This value varies according to the record characteristics and thus is broken down into three subfields.

I: Overhead requ.ired for a keyed record other than the last record on the track.

l: Overhead required for a keyed record that is the last record on the track.

K: Overhead bytes to be subtracted from I or l if the record does not have a key field.

(1 byte)-Further defines unique characteristics of the device.

Bits:

Tolerance:

Lobe

Is/track:

Directory Brocks/

Track

0':'5 : Reserved

6/7 : CC ·and HH must be used as I-byte values,as in the case of the 2321.A tolerance factor must be applied to all but the last recerd on the track.

(2 byte.s)-A value that is to be wed to determine the ef-fective length of the record on the track. The efef-fective length of a record is calculated in the following manner:

1 Add the key length to the data length of the record 2 Test bit 7 in the flag byte:

a. If 0, go to step 3

b. Multiply value from step 1 by the tolerance factor c. Shift result 9 bits to the right

3. Add overhead bytes to the result.

Note: Step 2 is not required if the calculation is for the last record on the track.

(1 byte)-A count of the number of labels that can be written on each track in the vrOC. (Number of full records of 44-bytes key md 96-bytes data lengths that can be contain-ed on one

track

of this device)

(l byte)-A count of the number of directory blocks that can be written on each track for an OS/VS partitioned data set.

(Number of full records of 8-bytes key and 256-bytes data lengths that can be contained on one track of this device)

-STANDARD DASD FII£ lABEL, FORMAT 4 ( ••• Cont 'd) FIELD NAME AND I£NGTH DESCRIPTION

9 DEVICE CONSTANTS The following illustrates the device con-( ••• Cont'd) stonts field for the various direct access

devices:

Device ~ HH Track

.! h !S f.!!a.

^!Q!.:. ~

~ ~

2311 203 10 3625 81 20 20 537 16

2314/2319 203 20 7294 146 45 45 534 25

3330 411 19 13165 191 191 66 512 39

3330·11 815 19 13165 191 191 56 512 39

,

3;J40135M8 350 12 8535 242 242 75 512 22

;; 3340/70MB 700 12 8535 242 242 75 512 22

3350 555 30 19254 257 267 82 8 512 46

Note: Labels per track = track length

-lOA

I + label length VSAM INDICATORS (19 bytes)

VSAM TIMESTAMP (8 bytes)

The VSAM indicators are present on any volume that contains space allocated to VSAM. If a volume does not contain any VSAM-owned space, these fields are set to zeros.

Is the time the most recent VSAM data space was added to the volume.

FIELD NAME AND I£NGTH DESCRIPTION

lOA VSAM CATALOG BllO-1 : This volume is owned by

(Cont'd) (I byte) a VSAM catalog,

Bit 1-7: Unused

TT of CRA Rela.tive track number of first track (2 bytes) of. catalog recovery area VSAM TIMESTAMP

(8 bytes)

lOB

RESERVED Reserved

(10 bytes)

11-14 VTOC EXTENT These fields describe the extent of the VTOC and are identical in format to fields 21-24 of the Format I file label. Extent type 01 (prime date area),

15 RESERVED Reserved

(25 bytes)

'--

^"~

STANDARD DASD FILE LABEL, FORMAT 5 ~ Format 5 Label used by OS/VS only)

rJ

^1eld 11

Available

Extent Available Extents in Key Available Extents

LKcy Identification

Available Extents

::;""'"

LFormat Identifier 281 29

Pointer to next

;- @FO,mot5

- ' " 0

-.0

I;;;

...

~

;::t

DESCRIPTION FIELD NAME AND LENGTH DESCRIPTION

FIELD 1

NAME AND LENGTH KEY IDENTIFICATION 4 bytes

Each of these four bytes is an hex 05. 3-9 AVAILABILITY EXTENTS These fields are identical, to field 2.

AVAILABLE EXTENT 5 bytes

This field indicates on extent of space avoil- 10 able for allocation to a data file. The first two bytes ore relative track address. The next two are the number of fu II cylinders included in the extent. The last byte is the number of tracks in addition to the cylinders in the ex-tent.

11-28

IN KEY 35 bytes They are in relative trock address sequence.

FORMAT IDENTIFIER 1 byte EBCDIC numeric AVAILABLE EXTENTS 90 bytes

POINTER TO NEXT FORMAT 5

-5: Format 5

These fields ore the same as field 2. There are 26 available extents fields in the Format 5 label.

Contains the address (in the form CCHHR) of the next Format 5 file label if one exists.

~

LABEL INFORMATION CYLINDER DEVICE TYPES

2314 3350 0'

2319 3330

3340 (see Note 2)

Track

o

,-BG(USRLABEL) .~

I

^BG ^(pARSTD)

I

F2 (USRLABEL) 3

I

^F2 ^(PARSTD)

I

^Fl (USRLABEL) 5

I

Fl (pARSTD)

I

(STLABEL)

1

7\ Standard Labels

llEE ,:~

1~ ~I

AddiHonalStanda;d

Lab~hl

LABEL Information Cylinder Layout and Record Format (see Note 1)

Temporary Standard (permanent) Temporary Standard (permanent) Temporary Standard (permanent)

Standard (permanent)

Note 1: The layout of the label infor-mation cylinder depends on the number of partitions defined in your system.

This example assumes that three partitions are present. For more information see DOSIVSE Serviceability Aids and Debugging Procedures.

Note 2: For the 3340, a second label

Dans le document DOS!VSE Handbook (Page 120-124)