FLASH memory cards contain a controller chip in addition to the FLASH memory devices. This controller chip provides the host interface to the card and gives it the ATA personality. There are various manufacturers of these "card controllers" and some provide support for the 2K linear access mode and some do not. It may actually be exceedingly difficult to find a CF format card supports the 2K memory mode and indeed it is far more common to find this support in PCMCIA type cards.

For example, please look at the following App Note from the SanDisk web site. It clearly states that the SanDisk controller does NOT support the memory mode on a CF card:

http://www.sandisk.com/pdf/oem/A...TAv1.0.pdf

On the other hand a visit to the following web page provides some information on a starting point to locate FLASH cards that do support the 2K byte paged linear access mode:

http://www.psism.com/linearflash.htm

If you search around it is possible to find compact flash cards that do support the linear acccess mode. Here are some web page links:

http://www.magicram.com/compact-Linear.htm
http://www.neutronexpress.com/prod.cfm/...ARD_SERIES

Here is a link to a FAQ that provides some information regarding OS compatibility issues with trying to use linear FLASH memory cards.

http://www.synchrotech.com/support/f...flash.html
http://www.synchrotech.com/support/w...-sram.html

The following link is to a rather dated document from the early to mid 1990's that discusses FLASH memory technology. It is interesting reading to see some of the historical roots about FLASH.

http://smithsonianchips.si.edu/ice/cd/ME.../SEC10.pdf

A final comment I would like to make.....any FLASH card that does support the 2K linear address mode must be connected to the host computer in a way so that the host computer bus provides the random addressing within the block window if the linear access mode is to be utilized. This is easy to provide if you are designing the complete system, such as making a microcontroller system. It is not so easy in the PC and Windows arena because 90% or more of the "sockets" that FLASH cards are read from are not wired to a bus inteface of the computer. This is particularly obvious for the cheap USB type external readers that are on the end of a serial interface.

In the beginning of PCMCIA cards back some 12, 15 or more years ago the linear address mode feature supporting the 2K paged mapped window was something that was taken for granted when the card interface was hosted directly on an ISA board with a direct connection to the ISA bus. Many of the original Intel card controllers provided this capability.

I have in-hand here also an ISA based FLASH memory card that is a disk emulation card. This card used a controller chip from M-Systems that provided dual 2K windows into the FLASH memory!

Application programs in DOS days....some of which I wrote....were particularly easy to make work with the linear accessed FLASH cards and boards.

Michael Karas