This application is titled “Quick filename lookup using name hash”.  Based on the title, it sounded like they are doing what TRS-DOS 2.0 did back in 1978, which is putting on the disk a hash table of filenames which then refer to directory entries.  TRS-DOS did that so that it usually only needed to read two sectors to look up a file, the HIT (Hash Index Table) sector, and the actual directory sector containing the file’s directory entry.  Otherwise they might have had to read multiple directory sectors to find the file if it existed, and all of the directory sectors if it did not.

The claims of the patent are a little difficult to interpret.  They refer to “a first one or more computer readable storage media having computer executable instructions…”.  This is basically referring to the disk/flash/etc. the operating system is booted from.  They refer to “a second one or more…” which is the disk/flash/etc. which holds the file system in question.

Here’s are two of the independent claims:

1. A first one or more computer readable storage media having computer executable instructions that, when executed on at least one processor, configure the at least one processor to perform a method of detecting if a target file name exists on a second one or more computer readable storage media, the method comprising:

(A) determining a name hash from the target name;
(B) determining if the name hash corresponds to a directory entry set name hash value, the directory entry set name hash value corresponding to one of a plurality of directory entry sets, each of the plurality of directory entry sets stored on the second one or more computer readable storage media;
(C) determining if the target name matches a directory entry set name corresponding to the one of the plurality of directory entry sets after step (B) determines the name hash corresponds to the directory entry set name hash value; and
(D) indicating that the target name exists after step (C) determines the target name matches the directory entry set name.

19. A method of detecting if a target file name exists, the method executing on one or more processors, the method comprising:

(A) determining a file name hash from the target file name;
(B) determining if the file name hash corresponds to a directory entry hash value, the directory entry hash value corresponding to one of a plurality of directory entries;
(C) determining if the target file name matches a file name, the file name corresponding to the one of the plurality of directory entries after step (B) determines the file name hash corresponds to the directory entry hash value; and
(D) indicating that the target file name exists after step (C) determines the target file name matches the file name corresponding to the one of the plurality of directory entries.

These seem to be to be to be *exactly* what TRS-DOS 2.0 did as early as 1978, so it seems possible that TRS-DOS could be used as prior art to invalidate at least these independent claims, and quite possibly some of the dependent claims as well.

So my question is, are there any published works documenting the TRS-DOS file system on-disk format, especially the use of the HIT table, other than “TRS-80 Disk and Other Mysteries” by H. C. Pennington?

This also seems to contradict the doctrine of first sale. Suppose Joe patents a new method and apparatus for exercising cats, and sells a product using this patent. When Fred buys the product, Joe has no more say in what Fred does with the product, because he has already been paid for the use of the patent for that product. In the absence of a separate, signed contract, Joe can’t tell Fred that his patent license is only good for twelve uses and that after that many he has to return or destroy the product. Nor can Joe tell Fred that he is not allowed to resell the product to a third party, or that the product cannot be used to exercise dogs instead.

Yet this Ninth Circuit ruling apparently gives manufacturers those controls over the use of patents after the first sale, despite the absence of an explicit contract.

I would urge people to boycott Lexmark, and not buy their printers or cartridges. And if you already have a Lexmark printer, I suggest civil disobedience in terms of always refilling the cartridges. But unfortunately this case sets a horrendous legal precedent, and it is likely that many other manufacturers will follow suit.