APPENDIX B
Common PEN*KEY 6000 Series Information
B-22 PEN*KEY
R
6200/6300 Hand-Held Computer Programmer’s Reference Guide
Definition of Terms
Conventional Memory
Ċ (Up to 640 KB) That area of memory in which most
DOS applications run. Other programs that could reside there include portions
of DOS and any programs called using a device=" or install=" line in the CONĆ
FIG.SYS file or any programs that are not executed with a loadhigh" from the
AUTOEXEC.BAT file.
UMA
Ċ Just above conventional memory. UMA provides memory for system
hardware. Any memory not used by the system is usable. The device=ump.sys. .
." and DOS=UMB" lines, in the CONFIG.SYS file, provide access to UMA. After
UMP.SYS is loaded and DOS=UMB" specified, other drivers are loaded into
UMA using devicehigh=" in the CONFIG.SYS file or loadhigh" in the
AUTOEXEC.BAT file.
HMA
Ċ Memory residing above conventional and upper memory. If
DOS=HIGH" is specified in the CONFIG.SYS file, this loads part of DOS into
HMA. This is possible if HIMEM.SYS is loaded before the DOS=HIGH" stateĆ
ment. This frees up some conventional memory but lowers the available memory
used for the RAM drive by 64 KB, because HMA contains the lower 64K of exĆ
tended memory.
This combination of conventional and upper memory consists of 1 MB, thus there
is 384 KB of memory for UMA.
Extended Memory
Ċ Above UMA and includes HMA. To access extended
memory, add device=d:\himem.sys" to the CONFIG.SYS file (where d:\" is the
drive and directory where HIMEM.SYS exists). The most widely known applicaĆ
tion using extended memory is MS Windows.
Expanded Memory
Ċ Type of memory simulated by using a program such as
EMM386.EXE, and used by a few specific programs. Applications created with
the PenRight! development environment are examples of programs that optionĆ
ally use extended memory. EMM386 can use UMA and extended memory to
simulate expanded memory.
Statements and Programs (CONFIG.SYS, AUTOEXEC.BAT)
The statements in the left column of the table below can be either uppercase or
lowercase. They are shown in uppercase here for readability.
Statement
Description
DEVICE=
Loads or installs device drivers into conventional memory from CONFIG.SYS
DEVICEHIGH= Loads or installs device drivers into UMA from CONFIG.SYS
DOS=HIGH
Loads a portion of DOS into HMA when called from CONFIG.SYS
DOS=UMB
Allows programs to run in UMA when called from CONFIG.SYS
UMP.SYS
Provides access to UMA when called with device=" in CONFIG.SYS
EMM386.EXE
Simulates expanded memory when called with device=" in CONFIG.SYS
HIMEM.SYS
Provides access to extended memory when called with device=" in CONFIG.SYS
INSTALL=
Runs an application in conventional memory from CONFIG.SYS
LOADHI
Runs applications in UMA when called from AUTOEXEC.BAT
B. Common PEN*KEY
6000 Series Info.
