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Groups > alt.folklore.computers > #235375
| From | Rich Alderson <news@alderson.users.panix.com> |
|---|---|
| Newsgroups | alt.folklore.computers |
| Subject | Tops-10 filename/extension representation [was Re: Origin Of Filename Extension Dot Separator] |
| Date | 2026-08-25 16:15 -0400 |
| Organization | PANIX Public Access Internet and UNIX, NYC |
| Message-ID | <mddo6eqyn0w.fsf_-_@panix5.panix.com> (permalink) |
| References | (3 earlier) <116fdlv$24uet$1@dont-email.me> <116hu7n$32c3b$2@toylet.eternal-september.org> <%X0jS.2$XsQ3.0@fx01.ams4> <116j56b$3eghm$1@toylet.eternal-september.org> <Cp9jS.718071$DOD1.590862@fx17.ams4> |
Newsgroups appropriately trimmed.
Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> writes:
> On 25/08/2026 12:20 PM, Mr. Chang Man-wai wrote:
>> On 8/25/2026 3:28 AM, Johann 'Myrkraverk' Oskarsson wrote:
>>> This one is easy. You put the letter in an envelope, then put a name
>>> one the envelope. Then you put the same name on a credit card sized
>>> /index card/, and put the index card in the drawer that has the same
>>> first letter as the name you put on the envelope in the first place.
>> That's just a library trick
>> But in the naming method,
>> which is the file name?
>> Which is the file name extension? :)
> Yes, we have to wonder what's in a name. If I remember correctly, the
> FAT [1] file system has separate entries for the /filename part/ and the
> /extension part/. And even if FAT doesn't have it, we can still imagine
> a file system that does.
On disk, user file directories are made up of pairs of 36 bit words. The first
word contains the SIXBIT (ASCII values reduced by 40(8)) name, up to 6 characters,
and the second word contains the SIXBIT extension in the left halfword and a
pointer to the first block of the file in the right halfword. File attributes
such as protection, write date, etc., are stored in that first block.
On DECtape, things are a little different.
1. The directory block is block 100(10) = 144(8) on the tape (out of a total of
578(10) blocks).
2. The first 83 words of the directory are broken into 5 bit bytes, with each
byte containing the file number (1 through 22(10)) to which that tape block
belongs.
3. The next 22 words contain the SIXBIT name of the file, up to six characters.
4. The next 22 words contain the SIXBIT extension, up to three characters, in the
left halfword, six 0 bits, and the file creation date (low order 12 bits).
5. The last word contains a tape label, the SIXBIT name of the tape.
The date format led to the DATE75 problem, because only 11 years (from the epoch
date of 1 January 1964) could be represented. A revised date model stored 3 high
order bits of date in the unused bits 35 of the first 83 words, interleaved by 22
(that is, file 1's high order bits were in words 0, 22, and 44, and so on).
The 83 words can represent more blocks than exist in 22 files. Blocks are
reserved to a boot program, and get a "file number" of 36(8); blocks beyond 577 in
word 83 get a file number of 37(8).
--
Rich Alderson news@alderson.users.panix.com
Audendum est, et veritas investiganda; quam etiamsi non assequamur,
omnino tamen proprius, quam nunc sumus, ad eam perveniemus.
--Galen
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Re: Origin Of Filename Extension Dot Separator anthk@not.dev.null - 2026-08-17 23:57 +0200
Re: Origin Of Filename Extension Dot Separator John Levine <johnl@taugh.com> - 2026-08-18 00:07 +0000
Re: Origin Of Filename Extension Dot Separator Bob Eager <throwaway0008@eager.cx> - 2026-08-18 11:51 +0000
Re: Origin Of Filename Extension Dot Separator Rich Alderson <news@alderson.users.panix.com> - 2026-08-18 22:15 -0400
Re: Origin Of Filename Extension Dot Separator Rich Alderson <news@alderson.users.panix.com> - 2026-08-18 22:13 -0400
Re: Origin Of Filename Extension Dot Separator Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-23 07:32 +0000
Re: Origin Of Filename Extension Dot Separator Peter Flass <Peter@Iron-Spring.com> - 2026-08-23 07:40 -0700
Re: Origin Of Filename Extension Dot Separator Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-23 22:07 +0000
Re: Origin Of Filename Extension Dot Separator Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-24 07:27 +0800
Re: Origin Of Filename Extension Dot Separator vallor <vallor@vallor.earth> - 2026-08-24 01:31 +0000
Re: Origin Of Filename Extension Dot Separator Chris Ahlstrom <OFeem1987@teleworm.us> - 2026-08-25 15:02 -0400
Re: Origin Of Filename Extension Dot Separator Rich Alderson <news@alderson.users.panix.com> - 2026-08-23 23:36 -0400
Re: Origin Of Filename Extension Dot Separator "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-23 23:13 +0800
Re: Origin Of Filename Extension Dot Separator Lars Poulsen <lars@beagle-ears.com> - 2026-08-23 11:20 -0700
Re: Origin Of Filename Extension Dot Separator Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-23 22:11 +0000
Re: Origin Of Filename Extension Dot Separator Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-24 07:28 +0800
Re: Origin Of Filename Extension Dot Separator Rich Alderson <news@alderson.users.panix.com> - 2026-08-23 23:39 -0400
Re: Origin Of Filename Extension Dot Separator "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-25 01:15 +0800
Re: Origin Of Filename Extension Dot Separator Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-25 03:28 +0800
Re: Origin Of Filename Extension Dot Separator "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-25 12:20 +0800
Re: Origin Of Filename Extension Dot Separator John Levine <johnl@taugh.com> - 2026-08-25 15:34 +0000
Re: Origin Of Filename Extension Dot Separator John Ames <commodorejohn@gmail.com> - 2026-08-25 09:35 -0700
Re: Origin Of Filename Extension Dot Separator scott@slp53.sl.home (Scott Lurndal) - 2026-08-25 17:00 +0000
Re: Origin Of Filename Extension Dot Separator "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-28 20:07 +0800
Re: Origin Of Filename Extension Dot Separator Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-29 16:59 +0800
Re: Origin Of Filename Extension Dot Separator "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-30 04:13 +0800
Re: Origin Of Filename Extension Dot Separator Snidely <snidely.too@gmail.com> - 2026-08-25 11:22 -0700
Re: Origin Of Filename Extension Dot Separator Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-25 21:43 +0000
Re: Origin Of Filename Extension Dot Separator scott@slp53.sl.home (Scott Lurndal) - 2026-08-26 15:34 +0000
Re: Origin Of Filename Extension Dot Separator Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-29 17:08 +0800
Re: Origin Of Filename Extension Dot Separator "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-28 20:12 +0800
Re: Origin Of Filename Extension Dot Separator John Levine <johnl@taugh.com> - 2026-08-28 18:14 +0000
Re: Origin Of Filename Extension Dot Separator Rich Alderson <news@alderson.users.panix.com> - 2026-08-28 21:02 -0400
Re: Origin Of Filename ... text and civilization? doomsday? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-29 10:15 +0800
Re: Origin Of Filename ... text and civilization? doomsday? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-29 11:55 +0800
Re: Origin Of Filename ... text and civilization? doomsday? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-29 17:38 +0800
Re: Origin Of Filename ... text and civilization? doomsday? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-30 04:09 +0800
Re: Origin Of Filename ... text and civilization? doomsday? Rich Alderson <news@alderson.users.panix.com> - 2026-08-29 18:31 -0400
Re: Origin Of Filename ... text and civilization? doomsday? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-30 11:33 +0800
Re: Origin Of Filename ... text and civilization? doomsday? John Ames <commodorejohn@gmail.com> - 2026-08-31 09:34 -0700
Re: Origin Of Filename ... text and civilization? doomsday? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-09-02 22:59 +0800
Re: Origin Of Filename ... text and civilization? doomsday? John Ames <commodorejohn@gmail.com> - 2026-09-02 08:29 -0700
Re: Origin Of Filename ... text and civilization? doomsday? Peter Flass <Peter@Iron-Spring.com> - 2026-09-02 12:36 -0700
Re: Origin Of Filename ... text and civilization? doomsday? John Ames <commodorejohn@gmail.com> - 2026-09-02 13:00 -0700
Re: Origin Of Filename ... Babylon cuneiforms etched on bread? Exorcism? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-09-04 12:24 +0800
Re: Origin Of Filename ... text and civilization? doomsday? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-02 21:55 +0000
Re: Origin Of Filename ... text and civilization? doomsday? James Dow Allen <user4353@newsgrouper.org.invalid> - 2026-09-03 04:44 +0000
Re: Origin Of Filename ... text and civilization? doomsday? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-03 04:57 +0000
Re: Origin Of Filename ... text and civilization? doomsday? James Dow Allen <user4353@newsgrouper.org.invalid> - 2026-09-03 05:29 +0000
Re: Origin Of Filename ... text and civilization? doomsday? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-03 06:57 +0000
Re: Origin Of Filename ... text and civilization? doomsday? James Dow Allen <user4353@newsgrouper.org.invalid> - 2026-09-03 10:06 +0000
The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-03 18:29 +0800
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) John Ames <commodorejohn@gmail.com> - 2026-09-03 08:02 -0700
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) athel.cb@gmail.com <user12588@newsgrouper.org.invalid> - 2026-09-03 15:49 +0000
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) Tony Cooper <tonycooper214@gmail.com> - 2026-09-03 14:08 -0400
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) John Ames <commodorejohn@gmail.com> - 2026-09-03 11:34 -0700
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) Tony Cooper <tonycooper214@gmail.com> - 2026-09-03 18:01 -0400
Re: The Amarna Letters, Hebrew -- wait, which brew? Peter Flass <Peter@Iron-Spring.com> - 2026-09-03 15:26 -0700
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) Steve Hayes <hayesstw@telkomsa.net> - 2026-09-04 04:51 +0200
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) James Dow Allen <user4353@newsgrouper.org.invalid> - 2026-09-04 04:27 +0000
Re: The Amarna Letters, Hebrew -- wait, which brew? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-04 12:52 +0800
Re: The Amarna Letters, Hebrew -- wait, which brew? John Ames <commodorejohn@gmail.com> - 2026-09-04 08:15 -0700
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) Steve Hayes <hayesstw@telkomsa.net> - 2026-09-05 06:05 +0200
Re: The Amarna Letters, Hebrew -- wait, which brew? (was: Re: Origin Of Filename ... text and civilization? doomsday?) James Dow Allen <user4353@newsgrouper.org.invalid> - 2026-09-05 09:13 +0000
Re: Origin Of Filename ... text and civilization? doomsday? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-05 21:09 +0000
Re: The Amarna Letters, Hebrew -- wait, which brew? Malcolm Purvis <malcolm@purvis.id.au> - 2026-09-04 06:49 +1000
Re: The Amarna Letters, Hebrew -- wait, which brew? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-03 21:27 +0000
Re: Origin Of Filename ... text and civilization? doomsday? Peter Flass <Peter@Iron-Spring.com> - 2026-09-03 08:28 -0700
Re: Origin Of Filename ... text and civilization? doomsday? Rich Alderson <news@alderson.users.panix.com> - 2026-09-02 15:37 -0400
Re: Origin Of Filename ... text and civilization? doomsday? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2026-08-29 05:25 +0000
Re: Origin Of Filename ... text and civilization? doomsday? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-29 13:35 +0800
Re: Origin Of Filename ... text and civilization? doomsday? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2026-08-29 17:35 +0000
Re: Origin Of Filename ... text and civilization? doomsday? Chris Ahlstrom <OFeem1987@teleworm.us> - 2026-08-29 15:42 -0400
Re: Origin Of Filename ... text and civilization? doomsday? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2026-08-29 21:07 +0000
Re: Origin Of .... "say what?" "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-30 18:00 +0800
Re: Origin Of Filename ... text and civilization? doomsday? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-30 04:17 +0800
Re: Origin Of Filename Extension Dot Separator Charles Hope <clh@candehope.me.uk> - 2026-08-29 09:45 +0000
Re: Origin Of Filename Extension Dot Separator Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-29 17:14 +0800
Re: Origin Of Filename Extension Dot Separator "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-30 03:52 +0800
Re: Origin Of ..... Darklands the video game? Medieval Europe? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-30 04:24 +0800
Re: Origin Of ..... Darklands & the Holy Roman Empire? 15th century?? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-08-30 16:47 +0800
Re: Origin Of ..... Darklands the video game? Medieval Europe? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-31 17:08 +0800
Re: Origin Of ..... Darklands the video game? Medieval Europe? "Kerr-Mudd, John" <admin@127.0.0.1> - 2026-08-31 16:40 +0100
Re: Origin Of ..... Darklands the video game? Medieval Europe? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-03 00:06 +0800
Re: Origin Of ..... Darklands the video game? Medieval Europe? "Mr. Chang Man-wai" <toylet.toylet@gmail.com> - 2026-09-02 23:02 +0800
Tops-10 filename/extension representation [was Re: Origin Of Filename Extension Dot Separator] Rich Alderson <news@alderson.users.panix.com> - 2026-08-25 16:15 -0400
Re: Tops-10 filename/extension representation [was Re: Origin Of Filename Extension Dot Separator] Kragen Javier Sitaker <kragen@canonical.org> - 2026-09-05 10:14 -0300
Re: Tops-10 filename/extension representation [was Re: Origin Of Filename Extension Dot Separator] Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-09-05 21:11 +0000
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