everett@hpcvra.cv.hp.com. (Everett Kaser) (05/16/91)
With regard to HP's memory cards versus other manufacturer's memory cards,
about all I can say with any authority is that HP's memory cards for the
HP 95LX are designed to meet the PCMCIA release 1.0 standard.
From purely empirical testing (a VERY small sampling; I had access to only ONE
Poquet PC, ONE Poquet 64K memory card, and ONE Poquet 512K memory card) I
found that:
1) The Poquet 64K card would NOT work in the HP 95LX. Looking at the card
with DEBUG after formatting it on both machines, it appears that the
64K card is a 16-bit ONLY card, meaning that it is accessed a word at a
time ONLY. The PCMCIA standard specifies that compatible memory cards
must be able to be accessed EITHER a byte at a time OR a word at a time.
This was a fairly old card (made well before the PCMCIA standard was
released in August 1990. Since Poquet is a member of PCMCIA (along with
HP and tens of other companies), they have probably addressed this issue
since then, but only the Poquet company can say for certain.
2) The Poquet 512K card DID work in the HP 95LX. It appears to be an 8/16
bit card. However, I can't comment upon any the workability (or the
un-workability) of the Poquet 512K cards in general, as I only had a
sample of ONE, and others have commented that they've tried a number of
them, some working, some don't.
3) Of the three HP 512K memory cards that I tried in the Poquet, all worked
fine.
4) Neither of the two HP 128K memory cards that I tried in the Poquet worked.
Since both sizes of HP memory cards are spec'd exactly the same electric-
ally, and since Poquet doesn't offer a 128K memory card size, I have to
assume that the Poquet machine simply doesn't support that size card.
THIS IS PURE CONJECTURE ON MY PART.
Again, I can only give hard information for Hewlett-Packard products, and even
then only in an unofficial capacity. Mechanically, electrically, and logical-
ly, the HP memory cards were designed to the PCMCIA release 1.0 spec.
Another thing that I've noticed is that the Poquet PC that I had access to
only seemed to be able to handle cards that were formatted as a pseudo-floppy
(see below for definition of pseudo-floppy), and then only if it had 8
"sectors/track" (the BOOT sector contains this information). The HP 95LX
formats cards to 16 sectors/track, so the Poquet is unable to access cards
formatted by the HP 95LX. However, the HP 95LX can access cards that are
formatted with other than 16 sectors/track (even though it uses 16 when it
formats), so a card that is formatted by a Poquet IS useable on the HP 95LX,
assuming that the card is electrically compatible. (And that MAY be a big
assumption if the card is non-HP. HP cannot guarantee that any other manu-
facturer's cards meet the PCMCIA standard.) By using DEBUG to "tweak" the
sectors/track entry in the BOOT sector of an HP 95LX-formatted card, the Poqet
was then able to access it.
Now, the HP 95LX can format a memory card in basically two different ways:
1) PCMCIA CIS FORMAT
This is the default for the HP 95LX. This format uses the first 512 bytes
of the card for a Card Information Structure (CIS), as specified by the
PCMCIA standard. This CIS contains various information structures that
specify all kinds of things about the card. The rest of the card is then
formatted just like a simple pseudo-floppy (see 2 below), with the BOOT
sector starting at address 512 in the card, immediately after the CIS.
This is the format that you will get when format a card using the FORMAT
command in the SETUP program and when you run FORMAT A: from the DOS
prompt.
2) PSEUDO-FLOPPY FORMAT
This is a simpler format, to allow the exchange of information between
machines that don't understand or support the PCMCIA CIS format. Since
the standard was only released in August of 1990, the HP 95LX is one of
the first machines available that can use the PCMCIA format. Other
manufacturers are also rapidly adopting and using the standard. I don't
know whether Poquet has revised their machine yet to use the standard or
not, but their original machine did not and, hence, could not read/write
the default formatted HP 95LX cards. The pseudo-floppy format card is
a simple sequential logical layout of "disk" sectors on the card, with
sector 0 (the BOOT sector) at address 0, sector 1 at address 512, etc.
The HP 95LX can format cards this way by running the FORMAT command from
the DOS command prompt and typing
FORMAT A: /p
with the /p meaning "pseudo-floppy".
The only difference between the two formats is that the PCMCIA format uses the
first 512 bytes (one sector's worth) for the CIS, thus decreasing the memory
storage by 512 bytes and making the card unusable by systems that don't
understand the PCMCIA format. However, the PCMCIA format seems to be the
way the world is going (in order to allow a host of different machines in a
host of different environments (ie non-MSDOS) to access cards from other
environments.
All of the above comments regarding Poquet products are my own opinions and
in no way reflect those of Hewlett-Packard Company.
(All other disclaimers, implied and unstated, are disclaimed. Only one
disclaimer per customer. All disclaimers must be over the age of conception.)
Everett Kaser Hewlett-Packard Company
...hplabs!hp-pcd!everett work: (503) 750-3569 Corvallis, Oregon
everett%hpcvra@hplabs.hp.com home: (503) 928-5259 Albany, Oregon