THX1138 at dakotacom.net
Mon Aug 28 22:04:01 CDT 2006
Chuck Guzis wrote:
> On 8/28/2006 at 4:47 PM Don wrote:
>> No, those are file *permissions*.
> Are you asking, "Did any system keep file type information out of the file
> name?" The answer is "yes, several did". Here's part of a microcomputer
> floppy directory from a circa 1977 OS. Note that fiile dates show this
> disk was probably created around 1986 (yes, it's all in ASCII--no binary
> fields here):
> A$DIRECTORY 000000001500000016 SF 064032386
> ACONFIG.SYS 000160001610000016 DV 000010199
> AMT.PARTS 000170001702700017 DV 000010199
> ADX85M26D03 000180004643600046 LV 000080483
> AISAM.SYS 000470005814400058 SV 000080483
> A$AUTOSTART 000620006201300062 PV 000080483
> ARUN 000630009348700093 SV 000080483
> AMTMENU 001120013036800130 OV 000010199
> ALOCATE 001310014242700142 OV 000010199
> A$SBA.C 001430014400000143 II 003
> A$SBA.C@ 001450014800000145 MF 055
> First column is the file name, the second is the file allocation and length
> information. The third column is the file type and the record type.
> S=System D=data, L=boot loader, P=profile, O=binary object, I=ISAM index,
> M=ISAM data (there are other types). The second characters is the type of
> record F=fixed, V=variable, I=index. The fourth column is the record
> length and the creation date. By convention, ISAM index files take the
> name of the data file, with an "at" sign appended, though there was no
> particular system requirement for this.
> If you enter the name of a file that didn't have the O file type, the
> system won't execute it. Similarly, you can't open a file with anything
> other than the DV attributes for text display or editing. ISAM files are
> handled by the ISAM manager and nothing else. You can't do ANYTHING with S
> or L type files, not read them, not write them directly.
> I've seen other systems from the 70's with this kind of directory
> information. However, the idea of a file extension for certain types of
> files was contagious--note the CONFIG.SYS (well in advance of MS-DOS).
Yes, I *know* this has been done other ways in the past.
What I am trying to figure out is the rationale behind
why it has (apparently) migrated into the file *name*.
Valid (though silly!) arguments could include things like:
- portability (file system independance)
- efficiency (no need to have extra atributes *in* the file)
- The Evil Empire couldn't come up with anything more original
- "Just Because"
I.e. if you were starting from scratch *today*, why would
you chose to encode file types in file names? vs. some
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