90 lines
3.4 KiB
Plaintext
90 lines
3.4 KiB
Plaintext
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Configuration files in MSDOS 2.0
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In many cases, there are installation-specific configurations
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of the DOS that are need to be set up at boot time. It is
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considered ugly for a user/OEM to have to re-build the DOS to
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include special drivers or to include a particular number of
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device drivers. The configuration file allows a user/OEM to
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configure his system without extra work.
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The configuration file is simply an ASCII file that has
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certain commands for the boot task. The boot process is as
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follows:
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Disk boot sector is read. This contains enough code to
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read the DOS and the initial BIOS.
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This DOS and initial BIOS are read.
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A long jump to the BIOSINIT routine is made. A variety of
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BIOS initializations are done.
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A long jump to the SYSINIT routine in the SYSINIT module
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is made. This module (supplied by MICROSOFT) will
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initialize the DOS and read the configuration file
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CONFIG.SYS, if it exists, to perform device instalation
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and various other user settable things. Its final task is
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to EXEC the command interpreter, which finishes the
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bootstrap process.
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The following are a list of commands for the configuration
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file CONFIG.SYS:
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BUFFERS = <number>
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This is the number of additional sector buffers to add
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to the system list. The effect of several BUFFERS
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commands is to allocate a series of buffers.
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FILES = <number>
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This is the number of open files that the XENIX system
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calls can access.
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DEVICE = <filename>
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This installs the device driver in <filename> into the
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system list.
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BREAK = <ON or OFF>
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If ON is specified (the default is OFF), a check for
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^C at the console input will be made every time the
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system is called. ON improves the ability to abort
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programs over previous versions of the DOS.
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SWITCHAR = <char>
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Causes the DOS to return <char> as the current switch
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designator character when the DOS call to return the
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switch character is made. Default is '/'.
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AVAILDEV = <TRUE or FALSE>
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The default is TRUE which means both /dev/<dev> and
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<dev> will reference the device <dev>. If FALSE is
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selected, only /dev/<dev> refers to device <dev>,
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<dev> by itself means a file in the current directory
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with the same name as one of the devices.
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SHELL = <filename>
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This begins execution of the shell (top-level command
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processor) from <filename>.
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A typical configuration file might look like this:
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BUFFERS = 10
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FILES = 10
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DEVICE = /bin/network.sys
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BREAK = ON
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SWITCHAR = -
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SHELL = a:/bin/command.com a:/bin -p
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The default value for BUFFERS is OEM specific in that the
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OEM can specify the number in the BIOS. A typical value is 2,
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the minimal value is one. The default value for FILES is
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usually 8 (as above it may be set by OEM BIOS) , so "FILES =
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10" actually allocates only 2 new file channels. If a number
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less than or equal to five is specified, the command is
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ignored. BREAK defaults to OFF, SWITCHAR to /, and AVAILDEV
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to TRUE. NOTE that the setting of SWITCHAR may effect
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characters used on the SHELL line (this is true of
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COMMAND.COM).
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