filename

This specifies the filename (and path) of the file containing the DASD image.

origin

Specifies the relative block number within the DASD image file at which the mini-
disk begins. The number must be less than the number of blocks in the file. The
default origin is zero.

numblks

Specifies the number of 512-byte blocks in the minidisk. This number must not
exceed the number of blocks in the file minus the origin. If omitted or specified as
an asterisk (“*”), then the minidisk continues to the end of the DASD image file.

SF=

Specifies a shadow file for the DASD device. Please refer to the following CKD
DASD section for information regarding the use of the SF=shadow file option.

shadowfile

This is the base name of the shadow file. The handling of shadow files for FBA
devices is identical as that for CKD devices. Please refer to the following CKD
DASD section for information regarding the use of the SF=shadow filefile option.

SYNCIO

SYNCIO enables possible synchronous I/O and is explained in detail in the fol-
lowing CKD DASD section.

ipname

This is the host name or IP address of the system, where the Hercules shared
device server is running.

port

This is the port number the shared device server is listening on. If the port is omit-
ted then the default is 3990.

devnum

Devnum specifies the device number on the shared device server. If the device
number is omitted then the default is the current device number on the local
system.

COMP=n

This keyword requests that the data has to be transferred compressed between the
client and the server. The argument n specifies the compression level (1-9). Values
closer to 1 mean less compression but also less processor time to perform the
compression. Values closer to 9 mean the data is compressed more but also more
processor time is required to compress the data.

6.10.4 Examples

Example 1:

Define a 3310 FBA DASD device on device address 0120. The name and path of the file containing the
DASD image is "D:/DASD/TST001.FBA".

0120 3310 D:/DASD/TST001.FBA

Example 2:

Define a 3370 FBA DASD device on device address 0120. The DASD device is attached to a shared
device server which is running on a machine with IP address 192.168.200.1 and listening on port 3990.
The device address of the DASD on the shared device server is 0121.

0120 3370 192.168.200.1:3990:0121

6.11 CKD DASD De
vices

6.11.1 Function

This device statement is used to define a CKD DASD device to the Hercules configuration. The argument
specifies the name of a file that contains the CKD DASD image or the INET address of a Hercules shared
device server.

The file consists of a 512-byte device header record followed by fixed length track images. The length of
each track image depends on the emulated device type and is always rounded up to the next multiple of
512 bytes.

Volumes larger than 2 GB (for example the 3390, model 3) can be supported by spreading the data
across more than one file. Each file contains a whole number of cylinders. The first file (which contains
cylinders 0-2518 in the case of a 3390) usually has “_1” as the last two characters of its name. The
ckddasd driver allocates the remaining files by replacing the last characters of the file name by the
characters “_2”, “_3” and so on.

If your operating system supports large file sizes (or 64-bit offsets) then volumes larger than 2GB can be
kept in a single file. The two character suffix is not used in this case.

Alternatively the argument may specify the name of a file containg a compressed CKD DASD image
(CCKD DASD files). The CKD driver will automatically detect whether the file contains a regular CKD
image or a compressed CKD image.

6.11.2 Syntax

Descriptive

filename [sfshadowfile

type]

or

ipname [ ] [
] n]

Diagram

Êʬ¬¬ ¬¬¬ ¬¬¬ filename ¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

shadowfile

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬ÊÍ

type