The contents of each record in cylinder 0 track 0 are as follows: RO Nothing. R1 IPL record -- Puts the system into wait state if storage volume is
loaded beforeCP nucleus is built.
R2 Checkpoint record
for awarm start. Used by CP to save and retrieve inforaation
R3Voluae label -- Same as OS VOL1 label. On CP systea residence volume, area in data record marks the beginning of the system directory. A label is automatically written when cylinder 0 is formatted. The owner field of the label record contains "VB/310" if there is allocation data present in R4.
R4 Allocation ByteMap Bach byte identifies a cylinder and
specifies its usage (paging, spooling I directory, and so on). Thisaap is filled in by the ALLOCATB function of the D!KF!T service
program.
RSForaat 4 as DSCB type label --For compatibility with os. Also,
theIBCDASDI prograa uses this label to keep a record of how aany alternate tracks remain available for assignment on this disk. The
Format/Allocate program will preserve this information by first
reading it fro.any existing Foraat 4 label, and then writing it
back in the new label.
R6Format S OS DSCB type label For coapatibility with as. Label
indicates to os that no space is available cn this voluae.
FR Is one ormore filler records.
Format/Allocateprogram control statements may be supplied in card form via a card reader, or may be entered at the system console. All error messages regarding improper specification of control statements
are displayed at the console.FORHAT/ALLOCATB PROGRAH CIRD INPUT Punch control statements for card input
field is separatedfrom the adjacent field
row cause the insertion of a default value.
the insertion of two default 114 VM/310 OFerator's Guide
start incoluan 1, and each by a comma. Two co •• as in a
Threecommas in a row cause
loaded before
R2 Checkpoint record
for a
R3
R4 Allocation Byte
specifies its usage (paging, spooling I directory, and so on). This
program.
RS
the
Format/Allocate program will preserve this information by first
reading it fro.
back in the new label.
R6
indicates to os that no space is available cn this voluae.
FR Is one or
Format/Allocate
are displayed at the console.
field is separated
row cause the insertion of a default value.
the insertion of two default
start in
Three