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Parameter

use_io_file_buffering[N]

N=0…7

Type

Text String

Value

Instructs CHARON-VAX to enable host operating system I/O cache on reading/writing operations.

The following values are possible:

"true" or "write-back" - the "write back" caching mode is used
"write-through" - the "write through" caching mode is used
"false" - caching is switched off

Note that this caching has a significant effect only in case of mapping to disk and tape containers, not physical drives.

When enabled, host operating system I/O cache may significantly improve I/O performance of the virtual system. At the same time maintaining I/O cache requires additional host resources (CPU and memory) which may negatively affect overall performance of the virtual system.

Initially is set to "false".

Example:

set PAA use_io_file_buffering[0]=true

These parameters are configured with the "set" command.

Example: Standalone VAX system with 2 virtual DSSI disks on a PAA SHAC controller

set session hw_model="VAX_4000_Model_108"

load virtual_serial_line/chserial OPA0 port=10003 application="putty.exe -load OPA0"

set quart line[3]=OPA0

set PAA container[0]="C:\Charon\Disks\dia0-rz24-vms-v6.2.vdisk"

set PAA container[1]="C:\Charon\Disks\dia1-rz24-vms-v6.2.vdisk"

The emulated VAX 4000 model 106 or 108 can then boot VMS with the following command:

>>> BOOT DIA0

After logging into VMS, the “SHOW DEVICE D” command displays the following:

$ show devices d

Device                 Device           Error Volume         Free Trans Mnt
Name                  Status           Count    Label        Blocks Count Cnt
004200$DIA0:           Mounted              0   DSSI01         32022   147   1
004201$DIA1:           Online               0

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HSD50 storage controller

To connect a storage controller to the virtual DSSI network, the CHARON-VAX configuration file must load at least one emulated HSD50 storage controller. In most cases one emulated HSD50 storage controller per virtual DSSI network is enough. The CHARON-VAX configuration file must supply a unique reference name for that instance. Even though this name is only valid within the configuration file, it is recommended, for clarity, to use the VMS SCSNODENAME as the instance name.The line below loads an emulated HSD50 storage controller, assigns it the instance name SCSNODE and connects it to the primary built-in DSSI controller:

load HSD50 MYDISKS dssi_host=PAA

The HSD50 emulation has the following configuration parameters:

dssi_host

Parameter	dssi_host
Type	Text String
Value	A string value that specifies the instance name of an emulated SHAC host adapter serving the virtual DSSI network.

If this value is not set, CHARON-VAX will try to locate the host adapter automatically. This automatic lookup works only if the CHARON-VAX configuration has exactly one instance of an emulated SHAC host adapter.

dssi_node_id

Parameter	dssi_node_id
Type	Numeric
Value	An integer value that specifies the address of an emulated HSD50 storage controller on the virtual DSSI network.

Possible values are from 0 through 7 (initially set to 0).

scs_node_name

Parameter	scs_node_name
Type	Text String
Value	A string value that specifies the SCSNODENAME of the emulated HSD50 storage controller.

The string can contain as many as 6 characters. Possible characters are uppercase letters: A through Z, and the integers: 0 through 9.

Initially set to the name of the emulated HSD50 controller. Therefore, the name of the emulated HSD50 controller should follow the above rules.

scs_system_id

Parameter	scs_system_id
Type	Numeric
Value	An integer value that specifies the SCSSYSTEMID of the emulated HSD50 storage controller.

Initially set to an arbitrary value that is guaranteed to be unique within the running emulated VAX 4000 model 106, 108, 700 and 705 node.

mscp_allocation_class

Parameter	mscp_allocation_class
Type	Numeric
Value	An integer value that specifies the ALLOCLASS of the emulated HSD50 storage controller.

Possible values are 0 through 255 (initially set to 0).

container

Parameter	container[N]

N=0…9999
Type	Text String
Value	A string value that specifies the container of the storage element with MSCP unit number: N. This storage element might be either a (virtual) disk or tape. In VMS running on an emulated VAX 4000 node, these storage elements appear as HSX00 disks (DUAN:) or HST00 tapes (MUAN:).

Possible values of the parameter are strings in one of the following forms:

Physical disk drives
- "\\.\PhysicalDrive<X>", where X is 0, 1, …
- "\\.\PhysicalDrive(DevID =XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX)"
  DevID addresses the target physical disk by its WWID
  (hexadecimal 128-bit identifier assigned to the disk
  drive by its manufacturer/originator).

- Example:
  Div
  class small
  set DISKS container[2]="\\.\PhysicalDrive(DevID= 6008-05F3-0005-2950-BF8E-0B86-A0C7-0001)"
  .
iSCSI disks
- "\\.\PhysicalDrive(iScsiTarget = <iSCSI target>, LUN = <LUN number>)"
  iScsiTarget addresses the disk by its iSCSI target name.
  LUN specifies LUN on connected iSCSI disk.

- Example:
  Div
  class small
  set DISKS container[3]="\\.\PhysicalDrive(iScsiTarget= iqn.2008-04:iscsi.charon-target-test1, LUN= 1)"
  .
Physical tape drives recognized by Windows
- "\\.\Tape<X>", where X is 0, 1, …
  .
Physical tape drives not recognized by Windows
- "\\.\Scsi<X>:<Y>:<Z>:<N>"

- Use the utility "Host Device Check" to find the values of X,Y,Z and N
  .
Floppy drives
- "\\.\A:" or
- "\\.\B:"
  .
CD-ROM drives (read-only)
- "\\.\CdRom<X>", where X is 0, 1, …
  .
CHARON-VAX disk images
- [<drive>":\"<path-name>"\"]<file-name>[".vdisk"]
  .
CHARON-VAX tape images
- [<drive>":\"<path-name>"\"]<file-name>".vtape"
  .

This parameter is initially not set, thus creating NO storage elements on the controller

media_type

Parameter	media_type[N]

N=0…9999
Type	Text String
Value	Overrides the default (automatically determined) MSCP media type of the device.

Syntax:

"<device-name>,<device-type>"

where:

<device-name> is either: “DU”, “MU”, “DK”, “MK”, “SCSI”, “DI”, “MI”, “DSSI”, “DJ” or “MJ”
<device-type> is the form of: “LLD” or “LLLD”, where “L” is a letter from A through Z, and “D” is a decimal number from 0 through 99

If not specified, the device name is set to “DI” and the device type is selected based on disk size for disk storage elements. For tape storage elements, the device name and type are set to "MI" and "TF86" respectively.
Initially not specified.

geometry

Parameter	geometry[N]

N=0…9999
Type	Text String
Value	This formatted string value specifies the explicit geometry of the disk storage element with DSSI node ID: N and MSCP unit number: N. This parameter is not applicable to tape storage elements.

The string format is <X>”/”<Y>[“/”<Z>] where:

X is the number of sectors per track
Y is the number of tracks per cylinder
Z (optional) is the number of cylinders on the unit. If omitted, Z is calculated based on X, Y and the total number of sectors on the unit that reflects the size of the disk storage element

If this parameter is not set, CHARON-VAX will configure the geometry based on the most probable disk type.

Initially not set.

The syntax above is applicable only to disk storage elements.

If the container is a tape image, the following format is used:

Syntax:

"<image-size>[, <early-warning-zone-size>]"

where:

<image-size> is the tape size in MB
<early-warning-zone-size> is the size (in KB) of the space left on the tape when a warning to the OS is issued. If omitted, 64K is assumed.

use_io_file_buffering

Parameter	use_io_file_buffering[N]

N=0…9999
Type	Text String
Value	Instructs CHARON-VAX to enable host operating system I/O cache on reading/writing operations.

The following values are possible:

"true" or "write-back" - the "write back" caching mode is used
"write-through" - the "write through" caching mode is used
"false" - caching is switched off

Note that this caching has a significant effect only in case of mapping to disk and tape containers, not physical drives.

When enabled, host operating system I/O cache may significantly improve I/O performance of the virtual system. At the same time maintaining I/O cache requires additional host resources (CPU and memory) which may negatively affect overall performance of the virtual system.

Initially is set to "false".

Example:

set DISKS use_io_file_buffering[0]=true

Example:

load HSD50 DISKS dssi_host=PAA dssi_node_id=5

The configuration file below emulates a VAX 4000 Model 108 node with one HSD50 storage controller serving two disks and another instance of an HSD50 controller that serves a tape drive to the VAX over a virtual DSSI:

Div

class	commandline

set session hw_model="VAX_4000_Model_108"

load virtual_serial_line/chserial OPA0 port=10003 application="putty.exe -load OPA0"

set quart line[3]=OPA0

load HSD50 DISKS dssi_host=PAA dssi_node_id=1

set DISKS container[0]="C:\Charon\Disks\dua0-rz24-vms-v6.2.vdisk"

set DISKS container[1]="C:\Charon\Disks\dua1-rz24-vms-v6.2.vdisk"

load HSD50 TAPES dssi_host=PAA dssi_node_id=2

set TAPES container[3]="\\.\Tape0"

In this example we emulate two

HSD50 instances

HSD50 instances. They are both connected to the same virtual DSSI bus, therefore we must assign them different DSSI node ID values.

Div

class	pagebreak

The emulated VAX 4000 Model 108 can boot VMS with the following command:

>>> BOOT DUA0

After logging into VMS, the “SHOW DEVICE D” and "SHOW DEVICE M" command displays the following:

Div

class	commandline

$ show devices d

Device                 Device Error    Volume Free Trans Mnt
Name                  Status           Count     Label    Blocks Count Cnt
DISKS$DUA0:           Mounted    0    DSSI01       31932   147 1
DISKS$DUA1:           Online 0
$ show devices m

Device Device Error Volume Free Trans Mnt Name Status Count Label Blocks Count Cnt TAPES$MUA3: Online 0

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Versions Compared

Old Version 7

New Version 8

Key

HSD50 storage controller

dssi_host

dssi_node_id

scs_node_name

scs_system_id

mscp_allocation_class

container

media_type

geometry

use_io_file_buffering