SECTION 7
System Information
7-2 PEN*KEY
R
6200/6300 Hand-Held Computer Programmer’s Reference Guide
ROM DOS 5
The ROM DOS 5 product, which is shipped in PEN*KEY flash memory, is
produced by Microsoft Corporation. Intermec Technologies Corporation selected
it for the PEN*KEY 6000 Series handĆheld computers, because it provides a
number of configuration options that can be selectively chosen when designing a
DOSĆbased system. The primary difference between ROM DOS 5 and MSĆDOS
5 is that much of the ROM DOS code executes from the upper memory address
space, using readĆonly memory. There are several ways in which the code can be
loaded. On the computer, the code is copied from flash into writeĆprotected
system memory, which is referred to as
shadow RAM
.
Since DOS is not loaded from disk, the IO.SYS and MSDOS.SYS files required
for booting from a disk are not required in this ROM DOSĆbased computer. The
initialization code, normally loaded from disk, is loaded from flash memory
instead. CONFIG.SYS is the first file read from a disk during the ROM DOS
boot process. Unless the CONFIG.SYS file contains a SHELL statement, the
following default shell statement is used:
SHELL=D:\COMMAND.COM /P D:\
All the CONFIG.SYS statements that MSĆDOS 5 supports are supported in
ROM DOS 5. This includes the
DOS=HIGH
and
DOS=UMB
statements provided by
MS DOS 5 to load data and DOS programs into the corresponding memory
areas. For DOS=HIGH to be useful, an XMS driver, such as HIMEM.SYS, must
be loaded. To use DOS=UMB, an XMS manager that supports the upper
memory functions must be loaded. A simple XMS driver named UMP.SYS is
available for using shadow RAM as upper memory.
UMP.SYS is much smaller and simpler than EMM386.EXE. Using shadow RAM
instead of XMS memory to provide upper memory, it provides more overall
memory to DOS and Windows applications. However, since UMP.SYS cannot
support expanded memory, EMM386.EXE is still the only method for providing
expanded (EMS) memory.
Using COMMAND.COM as Command Processor
The 6300 Computer comes with a full megabyte of flash. The standard MSĆDOS
5 version of COMMAND.COM is provided in flash. However, one change has
been made to COMMAND.COM to make it more useful on a 6300 Computer.
Whenever a critical error is encountered, the critical error message displays
numeric responses. As a result, it is possible to continue from a critical error
when no external keyboard is attached. If you are using an external keyboard
and prefer to use the unmodified version of COMMAND.COM, you can get it
from the toolkit. Use a SHELL statement in the CONFIG.SYS file to override
the default shell statement:
SHELL=A:\COMMAND.COM A:\ /P
MiniCMD
The 6200 Computer is equipped with MiniCMD.COM in flash, where space is at
a premium. It is a command shell alternative for COMMAND.COM. It is
provided by Microsoft Corporation in the ROM DOS 5 kit. It is about 19 times
smaller than COMMAND.COM: 2.5 KB versus 47 KB. This greatly reduced size
is MiniCMD's only advantage. Note that MiniCMD is renamed to
COMMAND.COM
in the 6200 Flash. To use the standard COMMAND.COM on
a 6200 Computer, you must provide it with your application. You can obtain a
copy of the COMMAND.COM from the toolkit.
7. System Information
