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COPY

DELETE

DIRECTORY

DISMOUNT

EXIT

HELP

INITIALIZE

MOUNT

RENAME

SHOW

TYPE

An Overview

CarriageControl

Command Formats

Invoking

Record Formats

Transfer Modes

Virtual Devices

Volume Formats

CARRIAGE_RETURN

FORTRAN

NONE

Verb

File-spec

/qualifier

device:

filename

.filetype

;version

Qualifiers

/CACHE

/MESSAGE

BINARY

STREAM

FIXED[=n]

PAD=[%b]c

Record Defaults

Creating

Example

RTEM Virt Devs

FILES11 Volumes

RT11 Volumes

DOS11 Volumes

Volume Defaults

Device Specs

File Specs

Device Specs

File Specs

Device Specs

File Specs

EXCHANGE — MicroVMS 4.6

Additional information available:

COPYDELETEDIRECTORYDISMOUNTEXITHELP
INITIALIZEMOUNTRENAMESHOWTYPE

An OverviewCarriageControlCommand FormatsInvokingRecord Formats
Transfer ModesVirtual DevicesVolume Formats

An Overview

                    EXCHANGE UTILITY (EXCHANGE)

 The Exchange Utility (EXCHANGE) is a utility program that is used
 with  mass-storage  volumes  that  are  formatted  for  operating
 systems other than VAX/VMS.  EXCHANGE can transfer files  between
 these  foreign  volumes  and  VAX/VMS native volumes, it can also
 perform volume-specific initialization and manipulation functions
 on  the foreign volumes.  It converts the format of the files, as
 appropriate,  when  transferring  files  between   volumes   with
 different structures.

 EXCHANGE performs file transfers and format conversions on:

       o  DOS-11 magnetic tape volumes
       o  Files-11 volumes
       o  RT-11 block-addressable volumes

 In addition to transferring files, EXCHANGE allows you to:

       o  Initialize foreign volumes, and scan for bad blocks
       o  List directories of volumes
       o  Delete files from block-addressable volumes
       o  Rename files on block-addressable volumes
       o  Write boot blocks on RT-11 volumes
       o  Mount and dismount foreign volumes

 EXCHANGE recognizes all Files-11 volumes on VAX/VMS devices.   It
 recognizes  DOS-11  formatted  volumes  on  9-track magnetic tape
 devices.

 EXCHANGE  recognizes  RT-11  volumes  on   any   VAX/VMS   block-
 addressable  device.   Note, however, that of the VAX/VMS devices
 RT-11 only supports the following devices:

      o  TU58 DECtape II data cartridge
      o  RL01 or RL02 cartridge disk
      o  RK06 or RK07 cartridge disk
      o  RX01 or RX02 floppy disk

 Also note that RT-11 imposes a size limit of 65535 blocks for the
 volume.  If an RT-11 volume is created on a device that is larger
 than this, the size of the  RT-11  volume  will  be  set  to  the
 maximum  and  blocks  65536  to  the  end of the volume cannot be
 utilized.

 EXCHANGE also supports a "volume" which is contained in a  VAX-11
 RMS  file  on  a  VAX/VMS  disk.  These files are termed virtual-
 devices.  The virtual-device file may be  manipulated  as  if  it
 were a block-addressable device.

 Files-11 Structure Level 1 or Files-11 Structure Level 2  volumes
 are  the  default  for  disk  volumes  initialized by the DIGITAL
 Command Language (DCL)  command  INITIALIZE.   DOS-11  and  RT-11
 volumes  are  initialized  using the EXCHANGE INITIALIZE command.
 Since the formats of these volumes are not recognized by VAX/VMS,
 the  volumes  must be mounted foreign, that is, by use of the DCL
 MOUNT command with the /FOREIGN or /NOLABEL qualifiers.  See  the
 VAX/VMS Command Language User's Guide for more information on the
 INITIALIZE and MOUNT commands.

CarriageControl

 The /CARRIAGE_CONTROL qualifier is used to specify  the  carriage
 control  attributes  of a file.  It is useful for Files-11 output
 files only.
              EXCHANGE /CARRIAGE_CONTROL
       Option                           Function
      ------------     -----------------------------------------
      CARRIAGE_RETURN  Implied carriage-return/line-feed control
      FORTRAN          FORTRAN carriage control record attribute
      NONE             No implied carriage control

 The full meaning of these attributes follows:

Additional information available:

CARRIAGE_RETURNFORTRANNONE

CARRIAGE_RETURN

           This attribute indicates that  each  record  is  to  be
           preceded  by  a  line  feed  and followed by a carriage
           return when the record is written to a carriage control
           device such as a line printer or terminal.  This is the
           default carriage control attribute.

FORTRAN

           The FORTRAN option sets  the  FORTRAN  carriage-control
           record  attribute, which means that the first character
           of each record is to be  interpreted  as  the  carriage
           control  specifier.   This option does not alter any of
           the actual data.  FORTRAN is only valid  with  Files-11
           output  files.  The FORTRAN option is incompatible with
           stream output to Files-11.

NONE

           This option specifies that there should be no  carriage
           control  implied  for the file.  Each record is assumed
           to contain the control characters necessary for  proper
           formatting.

Command Formats

 Most EXCHANGE command strings are very similar to the  analoguous
 DCL  command  for  native  volumes.   The  general  form  for the
 EXCHANGE command string is:

   verb/qualifier  file-spec/qualifier[,...]  [file-spec/qualifier]

 The second file-spec is only needed  for  commands  that  specify
 data transfers or require additional parameters.

Additional information available:

VerbFile-spec

/qualifier

Verb

      The verb defines the action to  be  performed  by  EXCHANGE.
      The verb is the same as the DCL command verb that performs a
      similar function on native volumes.  If no corresponding DCL
      command  exists,  the  verb is taken from the command on the
      foreign operating system.  Valid verbs are:

           COPY        Copy files from input to output spec
           DELETE      Delete files from block-addressable volumes
           DIRECTORY   List names of files on volume
           DISMOUNT    Dismount a volume
           EXIT        Return to the DCL command level
           HELP        Obtain help on EXCHANGE commands
           INITIALIZE  Create an empty volume
           MOUNT       Mount a volume on a device (foreign only)
           RENAME      Rename files on block-addressable volumes
           SHOW        Show volumes known to EXCHANGE
           TYPE        Display files on the default output device

      Since each of the verbs requires a particular command format
      and  set  of  qualifiers,  each  will  be  described  in  an
      individual section later in this document.  The  format  and
      applicable   qualifiers  will  be  described  in  the  later
      section.

/qualifier

      Any of the qualifiers allowed for the particular verb.   Multiple
      qualifiers can be used.  Some qualifiers affect the action of the
      command, others affect only the file-spec they follow.

File-spec

      The device name, directory, and/or file  name  for  the  EXCHANGE
      input or output device.  It has the general form:

           device:<directory>filename.filetype;version

      The following subfield definitions apply:

Additional information available:

device:<directory>filename.filetype;version

device:

           The device name can be either a standard VAX/VMS device name
           of  the  form  ddcu:  or a logical name that translates to a
           VAX/VMS device name.  If the device field is omitted  for  a
           reference,  the  current  default device is assumed.  When a
           virtual-device  is  mounted,  a  name  is  created  for  the
           virtual-device   which   is  used  as  the  device  name  in
           subsequent EXCHANGE commands.

           The directory on the volume which contains  the  file.   The
           syntax of the directory subfield is volume-specific.

filename

           The name field file specification for  an  input  or  output
           file.    The  exact  format  allowed  for  the  filename  is
           dependent on the volume format qualifier used.

.filetype

           The extension field of the file specification.

;version

           The version number of the file, if supported by  the  volume
           type.

Invoking

 You can use EXCHANGE interactively  or  as  a  DCL  command.   To
 invoke EXCHANGE interactively, enter the following in response to
 the DCL prompt:

      $ EXCHANGE

 The utility responds with the prompt:

      EXCHANGE>

 You can now enter any EXCHANGE command string.  To return to  DCL
 from the EXCHANGE> prompt, type EXIT or CTRL/Z.

 To use EXCHANGE as a DCL command, append the  command  string  to
 the EXCHANGE verb, as shown below.

      $ EXCHANGE DIRECTORY DMA1:/VOLUME_FORMAT=RT11

 This DCL mode command lists the directory  of  the  RT-11  volume
 mounted  on  DMA1:.   In  this  mode EXCHANGE executes the single
 command and returns to the  DCL  command  level.   Some  EXCHANGE
 features,  such  as  use  of  virtual-devices, require the use of
 multiple EXCHANGE commands.  Since EXCHANGE can  only  process  a
 single  command  in  DCL  command  mode, features which require a
 sequence of EXCHANGE commands are not available  in  DCL  command
 mode.

Additional information available:

Qualifiers

Qualifiers

 EXCHANGE allows two  qualifiers  on  the  EXCHANGE  verb  itself.
 These  qualifiers  must  be placed immediately after the EXCHANGE
 verb, they cannot be placed on the EXCHANGE command string.   The
 verb qualifiers are used to define conditions which are to remain
 in effect for the entire EXCHANGE session.

Additional information available:

/CACHE/MESSAGE

/CACHE

 /CACHE      (default)
 /NOCACHE

      Normally (i.e.  with the  default  /NOCACHE)  EXCHANGE  will
      attempt  to  reduce  the  number of I/O operations which are
      required to complete a command.  This  is  done  by  keeping
      certain  information,  such  as  the  volume  directory,  in
      memory.  At the completion of each  command,  EXCHANGE  will
      write  this  information  back  to  the  device.  The /CACHE
      option tells EXCHANGE to keep  this  information  in  memory
      until  EXCHANGE exits or the volume is dismounted.  This can
      result in improved performance on slower devices, especially
      the TU58 data cartridge.

/MESSAGE

 /MESSAGE      (default)
 /NOMESSAGE

      In the usual case (i.e.  with /MESSAGE in effect),  EXCHANGE
      will  print  a  status message when a volume is initialized,
      when a volume is mounted, and when a volume  is  dismounted.
      If  the  /NOMESSAGE  qualifier  is  used,  the  default  for
      EXCHANGE is to not print any messages  for  these  commands.
      This is most useful to keep unwanted messages from appearing
      when EXCHANGE is used in a command procedure.   For  further
      information,  see the description of the /MESSAGE qualifiers
      on the EXCHANGE INITIALIZE, MOUNT and DISMOUNT verbs.

Record Formats

   RECORD_FORMAT, CARRIAGE_CONTROL and TRANSFER_MODE Qualifiers

 EXCHANGE uses the /RECORD_FORMAT=option qualifier to  define  the
 internal  record  structure  of  a  file on a foreign volume.  An
 additional option to /RECORD_FORMAT defines a  related  attribute
 of the records.  The carriage control attributes for the file are
 defined  with  the   /CARRIAGE_CONTROL=option   qualifier.    The
 /TRANSFER_MODE  qualifier  can  be  used to specify that the data
 should be copied without translation as records.

    EXCHANGE /RECORD_FORMAT Options

       Option                           Function
      ----------     ---------------------------------------------
      BINARY         Identifies  PDP-11  formatted  binary  record
                       format
      FIXED          Identifies fixed-length record format
      STREAM         Identifies ASCII stream record format

      Record Attribute
      -----------------
      PAD            Sets the character to pad  short  records  on
                     fixed-length output, valid only with FIXED

 The three record format options (BINARY, FIXED  and  STREAM)  are
 mutually  exclusive;  only one of these options may be specified.
 Certain combinations of volume and record  format  and  attribute
 options are also invalid.

 On an input  file  specification,  the  /RECORD_FORMAT  qualifier
 gives  EXCHANGE  additional information to be used in reading the
 file.  This is needed  when  a  foreign  file  structure  is  not
 completely  self-describing,  or when a special interpretation of
 the file structure is needed.

 Input record format qualifiers are  never  required  on  Files-11
 input,  since Files-11 stores file attributes that allow EXCHANGE
 to correctly read the file.  The only option of this  group  that
 is  valid  for Files-11 input is the /TRANSFER_MODE=BLOCK option.
 In the absence of  an  explicit  transer  mode  option,  however,
 Files-11  input  files will have an implied /RECORD_FORMAT option
 of BINARY, FIXED or STREAM based on the actual record  format  of
 the  file.   If  a Files-11 file is not in a suitable format, use
 the DCL command CONVERT to change the file to the desired format.
 CONVERT  is  described  in detail in the VAX-11 Record Management
 Services Utilities Reference Manual.

 On an output file specification, the /RECORD_FORMAT qualifier  is
 used  to  specify  the characteristics that an output file should
 have after it is copied.  For Files-11 output, options are avail-
 able on the  /RECORD_FORMAT and  /CARRIAGE_CONTROL  qualifier  to
 provide commonly needed attributes.

 EXCHANGE  generates  Files-11  output   files   with   sequential
 organization  by  default.   The  default  Files-11 output record
 format is  Variable  if the  input  file  is  BINARY,  STREAM  or
 Variable  format, and FIXED if the input file has FIXED format or
 if /TRANSFER_MODE=BLOCK.  The default Files-11  carriage  control
 attribute is carriage-return.

 Three major record structure options exist.  These are:

Additional information available:

BINARYSTREAM

FIXED[=n]PAD=[%b]cRecord Defaults

BINARY


           BINARY record format is  valid  with  DOS-11  or  RT-11
           volumes.  BINARY files (also known as formatted binary)
           have variable-length records with headers and checksums
           added  to each record.  Formatted binary file format is
           described in  detail  in  the  RT-11  Software  Support
           Manual.   BINARY is not meaningful for Files-11 output,
           and will produce an error.

           On conversions from DOS-11 or  RT-11  BINARY  input  to
           Files-11  output,  EXCHANGE  generates  variable-length
           records.  The  output  record  size  equals  the  input
           record size.

FIXED[=n]

           Specifying a FIXED  format  transfer  always  reads  or
           writes fixed-length records.  No control information is
           stored in the file,  the  records  are  easily  located
           since they are all the same length.

           The FIXED=n option defines the length  of  fixed-length
           records.   In  the absence of an explicit length, FIXED
           format transfers default to  a  record  length  of  512
           bytes.

           As an input option, specifying a length is  only  valid
           for  non-Files-11 FIXED transfers.  It is not valid for
           STREAM,  Variable  or  BINARY  transfers,  because  the
           record  length  is  determined  by  the  delimiters  or
           control bytes.

           If any input records  are  longer  than  the  specified
           length,  the  records  will  be truncated and a message
           will be printed warning that one or more  records  were
           truncated.   If  input  records  are  shorter  than the
           output record, they  will  be  extended  with  the  pad
           character.   The  default  pad  character  is  the null
           character.  An alternate pad character can be specified
           with the PAD option.

STREAM

           Stream  ASCII  files  consist  of  ASCII  data  records
           terminated  by  carriage return/line feed (CR-LF), form
           feed (FF), or vertical  tab  (VT)  characters.   Stream
           files  are  sometimes called formatted ASCII files.  In
           transfers from DOS-11 or RT-11 STREAM files to Files-11
           Variable files, CR-LF pairs are removed from the end of
           records.  In transfers from Files-11 Variable files  to
           DOS-11  or RT-11 STREAM files, CR-LF pairs are added to
           the end of each record that does not already  end  with
           LF or FF.

           All null (NUL), delete (DEL),  and  vertical  tab  (VT)
           characters  are  removed  from  input records in any of
           these transfers.  ASCII data is  transferred  as  7-bit
           codes.   Bit 7 (sometimes used as a parity bit) of each
           byte is masked before transfer.

           If the RT-11 or DOS-11 file is (on input) or should  be
           (on  output)  an  ASCII  text  file  with  fixed-length
           records, use /RECORD_OPTION=FIXED=n rather than STREAM.
           Note that an ASCII stream file that happens to have all
           its records of the same length is not  the  same  as  a
           file   of  fixed-length  records.   STREAM  files  have
           records delimited by control characters.   FIXED  files
           have  no  delimiters;  records  are located by counting
           bytes.

           On  conversions  from  DOS-11  or  RT-11  to  Files-11,
           EXCHANGE  normally  generates  Files-11 variable-length
           records.  The  output  record  size  equals  the  input
           record    size.     Note    that    the    default   is
           RT-11 STREAM --> Files-11 Variable even  though  VAX-11
           RMS  supports  stream  format.  This choice was made so
           that a "typical" text file on RT-11 is converted  to  a
           "typical" text file on VMS.

           STREAM  may not  be used  with Files-11 output.   If  a
           VAX-11 RMS  stream format file  is desired,  create the
           Files-11 variable file, then use the CONVERT utility to
           create a STREAM  version of  the file.  Note,  however,
           that  since there are  slight differences  between  the
           VAX-11 RMS and the  RT-11  and  DOS-11  definitions  of
           STREAM  format,  such a  conversion might produce files
           with slight differences in control characters.

PAD=[%b]c

           The PAD option specifies which character will  be  used
           to  pad input records which are shorter than the fixed-
           length output record.  The default is to pad  with  the
           null   character  (value  zero).   /TRANSFER_MODE=BLOCK
           transfers are not padded.

           Pad characters are specified as follows:

                Option         Character

                PAD            NULL (00 Decimal)
                PAD=c          c is ASCII A-Z (capitals), or 0-9
                PAD="c"        c is any other ASCII character
                PAD=%bx        x is a number representing
                                 an ASCII character
                               b is the base of the number.
                                 Values for b are:

                                 D = decimal
                                 O = octal
                                 X = hexadecimal

Record Defaults

 EXCHANGE will assume  defaults  for  the  record  formats  if  an
 explicit  /RECORD_FORMAT  qualifier  is  not  used.  The defaults
 depend on several factors, and are chosen so that it will usually
 be possible to transfer files without a /RECORD_FORMAT qualifier.

 The  only  option  which  applies  to  Files-11  input   is   the
 /TRANSFER_MODE=BLOCK  option.   In  the  absence  of  an explicit
 /TRANSFER_MODE=BLOCK option EXCHANGE will determine the file  and
 record  attributes stored by VAX-11 RMS.  Therefore, on the basis
 of the actual record format of the  file,  Files-11  input  files
 will  have  an  implied /RECORD_FORMAT option of FIXED, STREAM or
 Variable.

 For DOS-11 and RT-11, EXCHANGE assumes  record  formats  for  the
 DOS-11 or RT-11 file based on type field of the file name.  These
 default record formats are:


           File Type                          /RECORD_FORMAT=

           OBJ, STB, BIN, LDA                 BINARY

           EXE, %LB, SAV, SML, SYS, TSK       FIXED=512


 All other DOS-11 and RT-11 file  types  will  be  assumed  to  be
 STREAM format when used as input file specifications.  When other
 file types are used for output files, the default  record  format
 will depend on the record format of the input file.

 These defaults will be applied  only  for  transfers  between  an
 RT-11  or  DOS-11  volume  and  a Files-11 volume.  For transfers
 between an RT-11 or DOS-11 volume and  another  RT-11  or  DOS-11
 volume,  no reformatting will occur unless explicit record format
 qualifiers request a conversion.

 In other words, EXCHANGE  will  usually  apply  a  record  format
 default  to  the input file, and let the input file record format
 so produced imply the output record format.  However, presence of
 one  of  the  file  types  in  the  above  table  for  an  output
 specification will override the default implied by the input file
 record format.

 The following table shows the output record  formats  implied  by
 various input record and volume formats.  The input format can be
 either defaulted, read from the file (for Files-11),  implied  by
 the  input  file  name type field or explicitly stated.  Remember
 that these default output formats will be  overridden  by  record
 formats implied by output file name type fields.


           Input       Input               Output      Output
           Volume      Record              Volume      Record

           FILES11     FIXED               FILES11     FIXED
                       /TRANSFER=BLOCK                 FIXED
                       STREAM                          Variable
                       Variable                        Variable

                       FIXED               RT11,DOS11  FIXED
                       STREAM                          STREAM
                       Variable                        STREAM
                       Variable (OBJ etc)              BINARY
                       /TRANSFER=BLOCK                 FIXED


           RT11,DOS11  BINARY (OBJ etc)    FILES11     Variable
                       FIXED (EXE etc)                 FIXED
                       /TRANSFER=BLOCK                 FIXED
                       STREAM                          Variable


      For transfers between RT-11 and  DOS-11  the  file  will  be
      copied   block-by-block  unless  a  format  conversion  (for
      example, Stream to Binary) is specifically requested.

Transfer Modes

 The /TRANSFER_MODE qualifier is used to specify the I/O method to
 be  used  in  a  transfer.   This option is useful for all volume
 formats.
               /TRANSFER_MODE Options
       Option                           Function
      -----------    ---------------------------------------------
      AUTOMATIC      Select  BLOCK  transfer  for  efficiency   if
                         possible
      BLOCK          Transfer block-by-block  without  looking  at
                         records
      RECORD         Transfer record-by-record

 A /TRANSFER_MODE=BLOCK transfer moves data between  devices.   No
 interpretation   is  done  on  the  data,  therefore  BLOCK  mode
 transfers are more efficient than  record  mode  transfers.   The
 block  sizes  on  both devices must be identical.  Both input and
 output   must   be   /TRANSFER_MODE=BLOCK   format.    Specifying
 /TRANSFER_MODE=BLOCK     on     one    parameter    will    imply
 /TRANSFER_MODE=BLOCK for the other file or device specification.

 A /TRANSFER_MODE=BLOCK transfer makes an exact copy of the  file.
 If  the  output device is Files-11, the file will be a sequential
 file  with  fixed-length  512-byte  records.   This  feature   is
 primarily  used  where  it  is  desired  to  absolutely avoid any
 interpretation of the data during the transfer.  If the  Files-11
 file  is  a  sequential  file with 512-byte fixed-length records,
 there is essentially no difference between a /TRANSFER_MODE=BLOCK
 transfer and a /RECORD=FIXED=512 transfer.

 A RECORD mode transfer  move  the  data  record-by-record.   This
 takes more time than BLOCK mode, but it is necessary if the input
 and output record structures differ.

 The default for EXCHANGE is to use AUTOMATIC transfer  mode.   In
 AUTOMATIC  mode, EXCHANGE will attempt to use BLOCK mode transfer
 whenever it is possible.  Block mode transfers are possible going
 from  RT-11  to  RT-11,  or  between  RT-11 and DOS-11, since the
 internal file structures are identical.  AUTOMATIC  wil  not  use
 block mode if either file specification contains a /RECORD_FORMAT
 qualifier.

 When the /LOG qualifier is used in a copy command, EXCHANGE tells
 the  size  of  the file which was transferred.  If BLOCK mode was
 used, the message will give the file size as the number of blocks
 transferred.   If  RECORD mode was used, the message will display
 the number of records.

Virtual Devices

 A virtual-device is a VAX-11 RMS file which contains an image  of
 a  foreign  block-addressable device.  EXCHANGE treats a virtual-
 device as a foreign volume.

 EXCHANGE must  be  used  in  interactive  mode  to  manipulate  a
 virtual-device.  This restriction is necessary because a virtual-
 device must be mounted before it can be accessed.  Since EXCHANGE
 only  executes  a single command in DCL mode, it is impossible to
 both mount  and  operate  on  the  virtual  device  in  a  single
 DCL-level command.

 The EXCHANGE> MOUNT /VIRTUAL command has two parameters (vs.  one
 parameter  for MOUNT /FOREIGN).  The first parameter supplies the
 name of the virtual-device, the second parameter is the  name  of
 the  VAX-11  RMS  file  which  contains  the  device  image.  The
 virtual-device name is thereafter used as if it were the name  of
 a  physical  device.   This  virtual-device name is essentially a
 logical name which EXCHANGE uses to  locate  the  virtual-device.
 For example:


   EXCHANGE> mount /virtual disk: virtual.dsk
   %EXCHANGE-S-MOUNTVIR, the RT-11 virtual volume DISK: has been
              mounted using the file DRA2:<DISKS>VIRTUAL.DSK;1

   EXCHANGE> directory disk:

   Directory of RT-11 volume DISK:      16-MAR-1983 08:30
                       using DRA2:<DISKS>VIRTUAL.DSK;1

     ANSI.COM      1 16-Mar-1983     QARINV.TXT    3 16-Mar-1983
     REASSI.COM   13 16-Mar-1983     SYSCRE.MAC    1 16-Mar-1983

   Total of 4 files, 18 blocks.  Free space 4944 blocks, largest 4474.

   EXCHANGE> copy /log sys$login:work.txt disk:
   %EXCHANGE-S-COPIED, _SLOTH$DUA17:<HOBBS.WRKD$.LOGIN>WORK.TXT;10
                         copied to DISK:WORK.TXT, 73 records

 The name "DISK:" is used exactly like a device name.  Be  careful
 not  to  assign  virtual-device  names  which are the same as any
 logical names that you might want to use.  EXCHANGE  will  assume
 that  any  use  of  the name refers to the virtual-device, rather
 than the logical name.

Additional information available:

CreatingExampleRTEM Virt Devs

Creating

 To create a new virtual device, use the  /CREATE  option  to  the
 EXCHANGE  INITIALIZE verb.  Use the /ALLOCATION option to set the
 size of the  virtual  device.   The  default  allocation  is  494
 blocks, the same size as a single-density floppy diskette.

Example

 To see an  extended  example  of  the  use  of  EXCHANGE  virtual
 devices, please examine the command file SYS$UPDATE:CONSCOPY.COM.
 This command file is used to  make  a  backup  copy  of  the  VAX
 processor  console  block  storage  volume.  It creates a virtual
 device and copies the console files to the virtual  device.   The
 restore  operation copies files from the virtual device back onto
 the console volume.

RTEM Virt Devs

 With one exception, EXCHANGE virtual devices are identical to the
 virtual  devices  maintained  by the VAX-11 RTEM (RT-11 Emulator)
 layered product.  EXCHANGE can manipulate RTEM  virtual  devices,
 and vice versa.

 The exception is that EXCHANGE does not fully recognize the  RTEM
 shared  virtual  volumes.   EXCHANGE  can  be used to read shared
 virtual volumes, but not  to  write  to  them.   When  the  MOUNT
 /VIRTUAL  command  is  given  on  an  RTEM shared virtual device,
 EXCHANGE will print a message that one or more directory  entries
 are  not  in  a  known  format,  and  that  the  volume  will  be
 write-locked to avoid corrupting the shared volume.

Volume Formats

 EXCHANGE  uses  the  /VOLUME_FORMAT=option  qualifier  to  define  the
 physical format of volumes to be processed.  A volume format qualifier
 determines what operations are allowed on the volume, and  will  often
 imply certain defaults.  A volume format qualifier also determines the
 format of the file name and directory specifications.

               Table 6-1:  EXCHANGE Volume Format Options

      Option                            Function

      FILES11        Identifies a Files-11 formatted native volume
      RT11           Identifies an  RT-11  formatted  block-addressable
                     volume
      DOS11          Identifies a DOS-11 formatted magnetic tape volume

 Volume format qualifiers must be attached to one or both of  the  file
 specification  parameters,  they  cannot  be  attached directly to the
 verb.

 Multiple volumes of different  volume  types  can  be  specified,  for
 example:

      EXCHANGE>  COPY  DMA1:*.FOR/VOLUME=RT11,MTA0:<11,132>*.FOR/VOLUME=DOS11  *

Additional information available:

FILES11 VolumesRT11 VolumesDOS11 VolumesVolume Defaults

FILES11 Volumes

 Files-11 is the standard volume format  maintained  by  VAX/VMS.   The
 mass-storage  formats  fully  supported  by  VAX/VMS are ANSI magnetic
 tapes and Files-11 disk structure  levels  1  and  2.   EXCHANGE  uses
 VAX-11 RMS for operations on these file structures.

Additional information available:

Device SpecsFile Specs

Device Specs

 Files-11  volumes  accept  the  standard  form   of   VAX/VMS   device
 specification  as  documented  in  the VAX/VMS Command Language User's
 Guide.  Files-11 disk volumes must be  mounted  without  the  /FOREIGN
 qualifier.

 The FILES11 option is  used  when  referencing  any  standard  VAX/VMS
 device,  even  though  the  Files-11  structure specifically refers to
 directory-structured devices such as disks, diskettes,  and  DECtapes.
 This  is  consistent with VAX-11 RMS, which allows unit-record devices
 (such as terminals) and magnetic tapes to be  accessed  in  a  device-
 independent fashion.

 If FILES11 is used when referencing a magnetic tape  device,  an  ANSI
 formatted  magnetic  tape  device will be implied.  The tape must have
 been mounted as an ANSI volume.  See the VAX/VMS Magnetic Tape  User's
 Guide  for  additional  information  on  the use of ANSI magnetic tape
 volumes.

File Specs

 Files-11  volumes  accept  the   standard   form   of   VAX/VMS   file
 specification documented in the VAX/VMS Command Language User's Guide.
 EXCHANGE allows unrestricted use of logical  names  in  Files-11  file
 specifications.   If  device  or  directory specifications are omitted
 from Files-11 specifications, the current  process  defaults  will  be
 used.

 Wild card  characters  are  valid  for  both  input  and  output  file
 specifications.  Version numbers should not be specified as wild cards
 when the foreign volume does not support version numbers, such as  for
 RT-11 and DOS-11.

 EXCHANGE permits output file specifications.  Any wild card fields  in
 the  output  file  specification  take the corresponding name from the
 input files.

RT11 Volumes

 The RT11 option is used to read and write block-addressable volumes in
 the  format  used  by DIGITAL's RT-11 operating system.  EXCHANGE does
 not restrict one to using  devices  that  are  actually  supported  by
 RT-11.

Additional information available:

Device SpecsFile Specs

Device Specs

 The device name for the RT-11 volume can be either a standard  VAX/VMS
 device name of the form ddcu:  or a logical name which translates to a
 VAX/VMS device name.  This device must have been mounted foreign,  for
 example   by  using  the  VAX/VMS  MOUNT  command  with  the  /FOREIGN
 qualifier.

File Specs

 RT-11 volumes do not have user directories, therefore the  RT-11  file
 specification has no directory field.

 The RT-11 character set for file names is the capital letters A-Z  and
 the  digits 0-9.  (These are RADIX-50 characters.) The file name field
 for RT-11 is six characters, the file type field is three characters.

 When a file with a name which is not valid under RT-11 is copied to an
 RT-11 volume, the RT-11 file name is produced from the first six valid
 characters of the name.  The RT-11 file type is  extracted  the  first
 three  valid  characters  of the input file type (for input names that
 are similar to Files-11 names).  Lowercase letters will  be  converted
 to uppercase before the check for a valid file name.  For example:

      EXCHANGE>  COPY/LOG  SYS_CREATE.MACRO_32  DMA0:
      %EXCHANGE-S-COPNEWNAME, DEVD$:<SYS.SRC>SYS_CREATE.MACRO_32;34
              copied to DMA0:SYSCRE.MAC (new name), 937 records

      EXCHANGE>  COPY/LOG  MTA0:"ANSI (A) TAPENAME"  DMA0:
      %EXCHANGE-S-COPNEWNAME, MTA0:<>"ANSI (A) TAPENAME".;1
              copied to DMA0:ANSIAT.  (new name), 321 records

 EXCHANGE permits renaming a file on a copy operation, so  any  desired
 file name can be supplied for the output file.

DOS11 Volumes

 The DOS11 option is used to specify that a magnetic  tape  is  in  the
 format  defined  by  DIGITAL's  early  PDP-11  Disk  Operating System,
 DOS-11.

Additional information available:

Device SpecsFile Specs

Device Specs

 The  DOS-11  format  is  supported  on  magnetic  tape  devices  only.
 Therefore,  a  VAX/VMS  device  specification for a 9-track tape drive
 must be present for DOS11 format.

File Specs

 DOS-11 volumes only accept directories in the user identification code
 (UIC)  format,  for  example  <310,22>.  The two numbers are octal and
 must be in the range 0 through 377.  When the directory  is  specified
 in an input file specification, either number or both may be indicated
 by a wild card character.

 The EXCHANGE DIRECTORY command uses a default directory of  <*,*>,  so
 that all the files on the tape will be listed regardless of the DOS-11
 directory.  For all other commands EXCHANGE uses your current  default
 directory,  if it is in UIC format;  otherwise, it uses your process's
 UIC as a directory.  If a file that appears in an  EXCHANGE  DIRECTORY
 command  is not found by another EXCHANGE command, reenter the command
 and specify the same directory which was displayed for the file in the
 DIRECTORY command.

 The DOS-11 character set for file names is the same as for RT-11,  the
 capital letters A-Z and the digits 0-9.  The DOS-11 file name field is
 nine characters long;  the file type field is three characters. * When
 a  file  with  a  name  which is not valid under DOS-11 is copied to a
 DOS-11 tape, the file name on the tape comes from the first nine valid
 characters  of the input file name.  The DOS-11 file type is extracted
 from the first three valid characters of  the  input  file  type  (for
 input  names  that  are similar to Files-11 names).  Lowercase letters
 will be converted to uppercase before the check for a valid file name.
 _______________
 * The original DOS-11 file name was a six-character  field.   The  RSX
   and  VMS FLX Utility extended the six characters to nine, in several
   steps as FLX evolved.  DOS-11 systems and older versions  of  RSX-11
   might  not  support  nine character file names.  These older systems
   will only see the first six letters of the file name.

 For example:

      EXCHANGE>  COPY/LOG  SYS_CREATE.MACRO_32  MFA0:
      %EXCHANGE-S-COPNEWNAME, DEVD$:<SYS.SRC>SYS_CREATE.MACRO_32;34
              copied to MFA0:SYSCREATE.MAC (new name), 937 records

      EXCHANGE>  COPY/LOG  MTA0:"ANSI (A) TAPENAME"  MFA0:/VOLUME=DOS11
      %EXCHANGE-S-COPNEWNAME, MTA0:<>"ANSI (A) TAPENAME".;1
              copied to MFA0:ANSIATAPE.  (new name), 321 records

Volume Defaults

 EXCHANGE will use default volume formats if an explicit /VOLUME_FORMAT
 qualifier  is  not  used.  The defaults are quite simple, yet powerful
 enough so that in practice it is almost  never  necessary  to  use  an
 explicit /VOLUME_FORMAT qualifier.

 EXCHANGE defaults to /VOLUME_FORMAT=FILES11 if a volume is mounted  as
 a  native volume, that is, mounted without /FOREIGN or /NOLABEL.  This
 applies to both block-addressable and magnetic tape devices.

 EXCHANGE defaults to /VOLUME_FORMAT=RT11 for block-addressable volumes
 (disks, diskettes, and TU-58 DECtapes) that are mounted foreign.

 EXCHANGE defaults to /VOLUME_FORMAT=DOS11 for  9-track  magnetic  tape
 volumes that are mounted foreign.

 Since EXCHANGE defaults to the current default device if no device  is
 given, entering a command sequence such as

      $ MOUNT/FOREIGN DMA0:
      $ SET DEFAULT DMA0:

 before invoking EXCHANGE will effectively cause EXCHANGE to default to
 the  RT-11  volume  DMA0:   for any file reference that omits a device
 specification.

Typewritten Software • bear@typewritten.org • Edmonds, WA 98026