dos
PURPOSE
Starts DOS Services.
SYNOPSIS
dos [ -anvx ] [ -c command ] [ file ]
DESCRIPTION
The dos command starts a DOS emulation environment. It
interprets DOS commands and runs programs that can use
the routines that simulate DOS runtime behavior. (For
more information on these routines and this environment,
see AIX Operating System DOS Services Reference and
Installing and Customizing the AIX Operating System.)
When you enter dos, a DOS environment file is created
from the process environment. (For details on how this
is done, see dosinit in AIX Operating System Technical
Reference.) Upon invocation, dos sets the current drive
to A: or the first valid drive. The environment variable
DOSDISK can be set to define the default current drive
(B:, C:, D, and so on).
The file parameter specifies a dos batch file to be run.
file must have the extension .bat or .BAT.
If the current DOS Services directory contains the batch
file autoexec.bat or AUTOEXEC.BAT, then DOS Services ini-
tially reads and runs commands from this file.
DOS commands are either built in (to the dos command
itself), or they are external. External commands reside
in the /usr/dos/bin directory. Normally, the search
order for commands that you enter is as follows:
o The directory /usr/dos/bin
o The working directory
o Each directory in the dos path.
When you enter a command, dos searches each directory for
a file with a name composed of the command name and
either the extension .BAT, the extension .bat, or no
extension. If the file has the extension .BAT or .bat,
it runs as a batch file. Otherwise, it runs as an AIX
program. If it is a AIX program, it can be either a com-
piled program or a shell file. In either case you must
have execute access to it.
The dos command supports two types of file systems: AIX
file systems and DOS file systems. Each dos minidisk can
contain either an AIX-formatted file system or a
DOS-formatted file system. However, diskette drives
(such as /dev/fd0) may contain only DOS-formatted file
systems, unless the device is mounted as an AIX file
system before you invoke dos.
Warning: Only one user or process at a time can access a
dos file system. If a dos file system resides on a mini-
disk, two or more users may attempt to access the mini-
disk at the same time. Because dos has no way to warn
you that another process is using a minidisk, you should
allocate minidisks containing dos file systems on a per-
user basis.
If a coprocessor on the system accesses a dos-formatted
minidisk at the same time as an RT PC process, there is
no conflict because only the first process has read/write
privileges. Subsequent opens at the device level are
limited to read-only access.
There are different restrictions for file names on DOS
drives and AIX drives. For DOS Services drives:
o File names cannot be longer than 12 characters.
o The name is always stored in uppercase.
o All files in the directory must have unique names.
o There can be only one period in a file name.
For AIX file systems:
o File names cannot be longer than 14 characters.
o Names may contain either uppercase or lowercase
letters.
o Two files in the same directory can have the same
name if the letter case is different.
o There can be more than one period in a file name.
o All files in the directory must have unique names.
On AIX drives, file names that begin with a period
specify hidden files. On DOS Services drives, hidden
files have a bit set in the attribute byte of the file
directory.
There are differences between AIX and DOS Services file
formats. AIX ASCII files and DOS Services ASCII files
are similar and can be converted from one format to the
other. Two new commands, FILETYPE and CONVERT, are
available for detecting and changing a file format.
DOS SERVICES COMMANDS AND PROGRAMS
There are several differences between the set of sup-
ported DOS Services commands and DOS commands.
Unsupported DOS Commands and Programs
You can use all of the standard DOS commands except
BREAK, CTTY, EDLIN, EXE2BIN, GRAPHICS, and SYS.
Modified DOS Commands
The following DOS Services commands behave differently
than the corresponding standard DOS commands:
backup The /M parameter is not valid for DOS Services
file systems.
chdir Unlike DOS, DOS Services may not allow you to
change to the highest directory in the file
system.
date This command lets only superuser change the
date.
dir Does not list file-name extensions in a separate
column when executed on an AIX drive.
format The /B is not supported. Two additional flags,
/U and /H are supported. Use the /U flag to
format a AIX diskette. Use the /H flag to
format a fixed disk to contain DOS Services file
systems in a single partition.
Note: The format command makes use of the mksf
command, which in turn uses the /etc/filesystems
file. If you modify this file, it will affect
the format command.
label On an AIX-formatted drive, the label is written
to a file called LABEL.VOL. Reading a label is
accomplished by reading this file. Changing a
label modifies the contents of this file.
Note: The command del *.* deletes the volume
label.
mode Only option 3 (for an asynchronous communi-
cations adapter) is supported.
print The DOS Services version does not ask you which
device to store the print queue on. This infor-
mation is set up in your user profile.
The /B, D, M, /S, /Q, and /U configuration flags
are not supported.
set A /U flag lets you display the AIX environment
as it is inherited by the dos command. You can
change the environment variables internal to
dos. When you exit from dos, the environment
variables remain unchanged.
time Allows only the superuser to change the time.
Additional Commands
In addition to DOS commands, the following commands are
available:
COMMAND The new flags which have been added to dos also
apply to this command.
CONVERT Converts a DOS format ASCII file to a AIX format
ASCII file or a AIX format ASCII file to a DOS
format ASCII file.
ed Starts the line editor.
EXIT Ends DOS Services. You can also use END OF FILE
(Ctrl-D).
FILETYPE Attempts to determine the format (AIX or DOS)
and contents of the specified file.
shutdown Provides for an orderly exit from the system.
FLAGS
-a Does not run the AUTOEXEC.BAT file.
-c cmd Runs the specified command.
-n Reads commands but does not run them.
-v Displays the commands and their flags as
they are read.
-x Displays the commands and their flags as
they are run.
FILES
/usr/dos/bin/* DOS Services external commands.
AUTOEXEC.BAT Batch file that can run commands automat-
ically.
autoexec.bat Batch file that can run commands automat-
ically.
RELATED INFORMATION
The following commands: "dosdel," "dosread" and
"doswrite."
The dosinit subroutine in AIX Operating System Technical
Reference.
The discussion of dos in Using AIX Operating System
DOS Services and AIX Operating System DOS Services Refer-
ence.