Vaughan Wesson, February 2003

Introduction

The PC Card standard was developed by the Personal Computer Memory Card International Association (PCMCIA) which was founded in 1989. A number of revisions to the standard have appeared over the years. The standard provides for both "memory" cards and "I/O" cards. Memory cards are typically SRAM cards and are accessed just like any other memory in the device. I/O cards on the other hand are accessed through a series of registers where the software can send "commands" to the device and receive "status" in return. Contrary to what you may think, all Flash and Disc drives supplied by the SRC are I/O devices rather than memory devices. This can be deduced by the ATA in their name (there is a whole history behind what ATA stands for that will only confuse you here).

CompactFlash devices were first introduced by SanDisk Corporation in 1994. They provide complete PCMCIA-ATA functionality and compatibility in a device that is much smaller than PC Cards. The CompactFlash Association was formed in 1995 as a non-profit mutual-benefit organisation to support the adoption of these devices. Their use in the last few years has taken off due to their adoption by a number of digital camera manufacturers. They may be used in PC Card sockets by utilising a simple and cheap passive adapter.

The Kelunji D Series recorders provide four PC Card sockets.

Attribute Memory

All PC Card compliant cards contain a special, separate memory area called attribute memory. Logically, this is a non-volatile memory area such as EPROM that contains information about the PC Card. It is defined in the PC Card Standard as the memory to hold the Card Information Structure (CIS) or Metaformat. The CIS contains information about what type of card it is, what power supply options it supports, what power saving features it supports, the manufacturer, model number and so on.

For ATA devices it includes information about the size of the data storage area and how this is organised.

For modem type devices, it includes information about what communication formats the modem supports.

Some of this information is displayed in the Kelunjis "Inspect:PC Card:Card info" menu.

Physical Sizes

PC Cards come in three different sizes. The length and width is the same in all cases (85.6 x 54 mm), it is the thickness that varies.

• Type I cards are 3.3 mm thick
• Type II cards are 5.0 mm thick
• Type III cards are 10.5 mm thick

CompactFlash cards come in two different sizes. The length and width is the same in both cases (36.4 x 42.8 mm). Their thickness is the same as the corresponding PC Card. In other words:

• Type I cards are 3.3 mm thick
• Type II cards are 5.0 mm thick

Guria Software

The Kelunji software supports both memory and I/O devices, but at present only uses these sockets for data storage devices. In future, PC Card modems may be supported as an alternative to external modems. Over the years, various changes have occurred in the support of data storage cards.

V5.01A

Initial file system only supported drives up to 32MB. Only supported SRAM cards

V5.01G : 1997-02-07

Added support for ATA Flash/disc cards

V5.03B : 1997-05-20

Fixed problem with determining size of 6MB SRAM cards

V5.04A : 1997-11-07

Support for multiple (32MB) partitions added

V5.05A : 1999-02-04

Added code to allow repartitioning and reformatting of devices. Increased the number of allowable drives/partitions from 14 to 26.

V5..06A : 1999-09-17

Completely changed the file system software being used. The new version supported large drives and allows triggered and continuous files to be created simultaneously

V5.07C : 2000-04-27

Fixed up operation with SRAM cards that had not been working for the last few versions

V5.08A : 2000-07-12

Fixed bug with inserting unformatted card

V5.09A : 2001-11-16

When formatting SRAM cards, it now determines the size of the card for itself. The "archive" status bit is now used to indicate files that have been copied. Switched to using "long" file names rather than the older DOS 8.3 type. Fixed a problem in the third party software when creating a file in a directory with many hundred files with "long" file names. Code change to support IBM MicroDrives

V5.09B : 2002-05-24

Code change to correctly power CompactFlash drives. Fixed problems with formatting larger drives. Users are now asked to remove a drive after it has been formatted. This ensures all internal state is correctly cleared

V5.10A : 2002-10-25

This version has problems with a number of types of PC Cards

V5.11A : 2003-02-xx

Incorporated an upgrade of the file system software. Supports the widest range yet of PC Cards

Cards Used by SRC

Since the first D Series were built, the SRC has used a wide variety of PC Cards and a reasonable number of CompactFlash cards. In addition, a number of our customers have purchased their own cards and have used them in Kelunji recorders. Below we list a number of these are indicate any issues or particular points of interest with each.

SRAM Based Cards

The SRC has used two types of SRAM based cards:

2MB - Unknown manufacturer

These devices do not actually conform with the PC Card standard at all as they contain NO attribute memory. However, we have added special code within the Kelunji software to test for and support this type of card. They use button batteries that are readily available from shops selling watch batteries. Other than batteries going flat, we have not had any real problems with these cards.

4MB - MagicRAM

These are the "industrial" version that include a rechargeable battery. They have only been used in KG1 boards in Kelunji Classics. No known problems.

6MB - MagicRAM

These devices use a rechargeable battery and seem to work fine. We have mostly been using these in Kelunji Classics rather than D Series, but have not found any problems with them.

PC Card Flash Cards

Flash memory based cards are a good compromise between the low capacity and high cost of SRAM cards and the high capacity, low cost but lower reliability of PC Card Discs. These cards are accessed in exactly the same way as a PC Card disc. That is, they are I/O based PC Cards containing their own microprocessor that manages the actual reading and writing of the Flash memory. The Kelunji software effectively says things like "Read block 2436" or "Write block 12345". Flash cards are usually Type II.

The SRC only has experience with a few brands of these.

10MB - Unknown manufacturer (plain silver)
20MB

These cards have been nice and reliable with no known problems.

16MB - Cannot remember
24MB

These cards have also been reliable with no known problems.

PC Card Hard Discs

Hard discs provide the largest data storage capacity of all PC Card options. However, it is fair to say that we have had problems with a number of these cards. Most PC Card hard discs are Type III, but some more recent ones are Type II.

The SRC has used a number of hard discs from Calluna who went in to receivership in around 2000. This is probably indicative of the problems we had with their cards.

260MB Type II - Calluna

Only had relatively few of these, but most have failed within 12 months of use.

340MB Type III - Integral Peripherals

We only ever purchased a few of these, but as far as I know they are still working fine!

520MB Type III - Calluna

We purchased approximately 100 of these for the Philippines project and general use. While most seemed to work fine for the first six to twelve months, the majority had failed within 18 to 24 months. They were being used in non-airconditioned offices in the Philippines doing continuous recording, but we have also had a number of units fail in the SRC office.

1040MB Type III - Calluna

We only ever owned one of these that was only ever used in the office. After a couple of years of very intermittent use, it seems to be dead.

2GB Type II - Toshiba

We have only ever purchased one of these. We tested this before supplying it to a customer and it seemed OK. We have not heard from the customer of any problems with the device.

CompactFlash Flash Cards

These have the same advantages as PC Card flash cards, but because of market demands and now considerably cheaper. We have found that a number of models just DO NOT WORK with the Kelunji D Series. We have not yet managed to resolve the problem. For at least some devices, it is a "hardware" problem in that we are not reading the correct information from the attribute memory.

Devices That Work OK

• DigiCard - 256MB
• Kodak - 32MB, 64MB, 96MB, 128MB
• Kingston - 512MB
• Legend - 32MB
• SanDisk - 128MB, 384MB

Devices That do NOT Work

• DigiCard - 128MB
• Pretek - 64MB?
• Verbatim - 64MB?

CompactFlash Hard Discs

When we first started looking at the IBM MicroDrives (the only brand of CompactFlash hard disc we have looked at), they did not work. We communicated with an engineer at IBM as we felt that the drives were not in complete conformance with the standard. A minor modification of the Kelunji software allows it to work with the MicroDrives without affecting its operation with other devices.

We have used the 512MB IBM MicroDrives without any problems to date. Geoscience Australia have been using 1GB versions and they have reported problems with bad blocks causing problems with the Kelunji software.