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TS-2200 User's Manual
Technologic Systems
4 Memory
4.1 DRAM
The TS-2200 has a total of 2 Megabytes of DRAM providing 640 KB of base memory, 1 Megabyte of
extended memory, and 128 KB of shadow RAM for the BIOS and DOS-ROM. This is identical to a
standard PC memory map. The Flash SSD is the exception -- see below for details.
As shipped, the 1 Megabyte of extended memory is used as a RAM disk by the vdisk.sys device
driver. The RAM disk is accessible as drive C: if the DiskOnChip Flash disk is not installed, drive D: if
it is. The size of the disk can be reduced to provide extended memory for an application (or simply
removed entirely) by editing the CONFIG.SYS file in the root directory of drive A:.
4.2 Flash
There is a total of 1 MB of Flash memory on the TS-2200. The top 128 KB of Flash are reserved for
the BIOS and DOS-ROM. During POST, they are copied from Flash into DRAM at addresses E0000h
through FFFFFh for improved performance (a standard technique known as BIOS Shadowing). The
remainder of the Flash memory (896 KB) is used by a SSD (solid state disk) appearing as drive A.
The SSD is fully supported by the BIOS as an INT 13h drive.
The physical Flash memory is accessed by the BIOS through a 64 KB memory mapped window at
addresses D0000h through DFFFFh. If you are installing a PC/104 daughter card that uses memory
mapped I/O, it must not conflict with this address range.
The Flash memory is guaranteed capable of a minimum of 100,000 write/erase cycles. This means
that if you completely erase and rewrite the SSD drive 10 times a day you have over 27 years before
any problems would occur. Reading the SSD produces no wear at all.
4.3 Flash Expansion
If 896 KB of Flash is insufficient for your application, an empty 32-pin socket is available for Flash
expansion using an M-Systems DiskOnChip 2000 or DiskOnChip Millennium Flash Drive. This product
is a wonder of miniaturization; it is a complete Flash SSD in a single 32 pin package currently
available in sizes from 4 MB up to 144 MB. The DiskOnChip is available from Technologic Systems
as well as other distributors. It is compatible with DOS as shipped, and drivers for other operating
systems are available.
When using the DiskOnChip, it will simply appear as drive C: The DiskOnChip is accessed through an
8 KB range of CE000h through CFFFFh in memory space. If you are installing a PC/104 daughter
card that uses memory mapped I/O, it must not conflict with this address range if the DiskOnChip is
installed. Additionally, the DiskOnChip firmware uses approximately 20 KB of user RAM (below 640
KB).
4.4 Battery-Backed SRAM
The 32-pin socket can also optionally hold 32 KB of battery-backed CMOS SRAM memory. This or the
DiskOnChip may be installed, but not both.
Battery backed SRAM provides non-volatile memory with unlimited write cycles and no write time
degradation, unlike Flash memory. The SRAM uses an additional 32 KB range of C8000h through
CFFFFh. If the SRAM is installed, PC/104 daughter card that uses memory mapped I/O must not
conflict with this address range.
The SRAM can be utilized as a RAM disk (drive C:) by the
device driver. The device
TSRAMDSK.SYS
driver can be added or removed (and the SRAM accessed directly) by editing the associated line in
the
file in the root directory of drive A:. Please see the BIOS/DOS User's Manual for
CONFIG.SYS
further information on
.
TSRAMDSK.SYS
11/06/2000
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