BOOTSTRAP LOADER

On early computers great efforts were expended on making the bootstrap loader short, in order to make it easy to toggle in via the front panel switches. It was just clever enough to read in a slightly more complex program (usually from punched cards or paper tape), to which it handed control. This program in turn read the application or operating system from a magnetic tape drive or disk drive. Thus, in successive steps, the computer "pulled itself up by its bootstraps" to a useful operating state.

Nowadays the bootstrap loader is usually found in ROM or EPROM, and reads the first stage in from a fixed location on the disk, called the "boot block". When this program gains control, it is powerful enough to load the actual OS and hand control over to it. A diskless workstation can use bootp to load its OS from the network.

BOOT DISK

There are several ways folks are getting their USB CDroms, Hard Drives, and other drives to work in DOS. One is using what's known as DUSE driver system. The second method is using what looks somewhat like standard CDrom driver files and a USB driver. Both methods appear to require loading an usbaspiX.sys file first in config.sys in most cases. The third method is a bootdisk from a USB vendor. Method 4 is getting good reviews also.
METHOD 1 - The DUSE System

Example 1 Using DUSE

[config.sys]device=a:\himem.sysdevicehigh=a:\emm386.exedevice=a:\usbaspi.sysdos=high,umb

Note: You can find a usbspi.sys on the internet or use on of the five different versions I've found in the Download Files section at the bottom of the page
[autoexec.bat]@echo offduseldr a:\duse.exeMSCDEX /D:USBCDROM /S /M:15 /V

Example 2 Using DUSE

[config.sys]device=a:\himem.sysDEVICE=a:\duse.exe
[autoexec.bat]MSCDEX /D:USBCDROM /S /M:15 /V

METHOD 2 - The usbaspi.sys/usbcd.sys System - Example 1

As noted, this method seems just like loading IDE drivers, with the added entry of the usbaspiX file. The following are the relevant portions taken from a modified config.sys and autoexec.bat file which was designed to work with a Windows 98 OEM Bootdisk with the ramdrive.

The complete config.sys and autoexec.bat replacement files are available for download below, and you might want to start first with just copying them to your OEM bootdisk along with the relevant drivers and then experiment later with getting them to work on your Customized disk.
[config.sys - example 1]device=himem.sys /testmem:offdevice=usbaspiX.sysdevice=usbcdX.sys /D:mscd001
[config.sys example 2 - USB Floppy in only port, "sometimes" allows switching to CDrom after boot]device=himem.sys /testmem:offdevice=ramfd.sysdevice=usbaspiX.sys /Wdevice=usbcdX.sys /D:mscd001
[autoexec.bat]LH %ramd%:\MSCDEX.EXE /D:mscd001 /L:%CDROM%

METHOD 2 - The usbaspi.sys/usbcd.sys System - Example 2
"I finally got my Belkin external drive enclosure with a WD 120gb drive to work in DOS, and then perform a GHOST image", wrote don b. "Here's the files and config.sys that worked."
[config.sys]device=himem.sys /testmem:offdevicehigh=usbaspi1.sysdevicehigh=di1000dd.sysdevicehigh=usbcd2.sys /d:USBCD001LASTDRIVE = Z
[autoexec.bat] don b. noted that either the standard Ghost or Win98X autoexec.bat worked as is.
METHOD 2 - The usbaspi.sys/usbcd.sys System - Example 3

Herbert H. writes: "I Just solved my problem by using the files from the "virtual" DOS drive ghost03 makes when you run interactive mode. It uses IOmega USB drivers and Guest.exe. It alowed me to use my Western Digital external USB HD in DOS.
[config.sys]LASTDRIVE=ZDEVICE = usbaspi4.sys /int /allDEVICE = usbaspi5.sys /int /allDEVICE = usbaspi5.sys /int /all /D1DEVICE = usbcdX.sys /D:cd2 DEVICE = OAKCDROM.SYS /D:cd1 [For his IDE CDrom]

METHOD 3 - The datoptic System

The key driver files in dat.exe include:
usbaspi.sys 37,090 bytesnj32disk.sys 15,808sbp2aspi.sys 28,836
datoptic.com recommends the following config.sys for it's USB/1394 products. It's been reported tho that their drivers also work for other brands as well.
[menu]menuitem=USB,USB Bootmenuitem=1394,1394 Bootmenudefault=USB,30menucolor=7,0
[USB]DEVICE = USBASPI.SYS
[1394]DEVICE = SBP2ASPI.SYS
[COMMON]DEVICE = NJ32DISK.SYS /RLASTDRIVE=Z

Default Drive

The default drive is the first disk drive on which DOS will look for a program if no drive specification is given with the filename.

How do you know what it is? Look at the prompt. The default drive letter is part of the prompt (unless someone has changed the prompt to eliminate it).

A:\> indicates that drive A (the left or top drive in a two-drive system) is the default drive. The right (or second) drive in such a system is called drive B and the first hard disk in any system is given the letter C as its drive designation.

DOS supports many more than drives A through C. In fact, if your computer has them you can specify up to 63 drive names. (This is a "Catch 22" situation. DOS can respond to 63 drive names but converts all lower case to upper case automatically so you really can't access 63 devices.) You change drives by typing the desired default drive followed by a colon at the prompt. To change to drive C type C: as shown here:

A:\> c:

C:\>

Device Names

Character oriented devices can be addressed by DOS through their names:

CON: The name for the video display and keyboard.
AUX: or COM1: This is the first asynchronous communications port which usually has a modem or other serial device connected to it. The second communications port is COM2:
PRN or LPT1: The first parallel printer port. PRN comes from printer and LPT is an old designator derived from line printer. A colon on PRN and all device names is optional in later DOS versions. The second parallel port is LPT2:
CAS1: A holdover; this is the cassette recorder port.
NUL: This is a test device. Anything sent to device NUL: goes into the bit bucket (i.e., gets thrown away).

Rules for Filenames

Like devices, disk files have to be identified so DOS can address them. These filenames have specific rules.

The basic form of a filename is:

Filename.ext

The first part of the name to the left of the period is called the root name. The root name can be from one to eight characters long and cannot be the same as a device name. The second part to the right of the period is the extension. It is optional and, if used, can be one to three characters long.

The period is used between the root name and extension and must be present if there is an extension.

The following are legal and illegal characters in a filename:

Legal: A-Z 0-9 $#&@!()-{}'`_~
Illegal: <>\^+=?/[]";,* plus control characters and the space

Some other operating systems allow longer file names and there are commercial utilities which link a database of long names to your short names so you can find files by using more fully descriptive names.