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From: William Corcoran <>
To: Richard Tobin <>
Cc: The Eunuchs Hysterical Society <>
Subject: Re: [TUHS] Unix filesystem semantics history - files with holes
Date: Thu, 11 Apr 2019 19:09:47 +0000
Message-ID: <> (raw)
In-Reply-To: <>

Sparse files: “Thin Provisioning” way ahead of its time.  Combined with the patented SUID: The UNIX marvels never cease.  

It just goes to show that all this marketing BS touted today has already been done before.  

Bill Corcoran 

On Apr 11, 2019, at 12:36 PM, Richard Tobin <> wrote:

>> When did the Unix filesystem add the semantics for "files with holes" (large,
>> sparse files)?
> It was there in the first edition:
> The FILE SYSTEM (V) man page includes a last paragraph identical to
> that of FILSYS (V) in seventh edition:
>  If block b in a file exists, it is not necessary that all blocks
>  less than b exist.  A zero block number either in the address words
>  of the the i-node or in an indirect block indicates that the
>  corresponding block has never been allocated.  Such a missing block
>  reads as if it contained all zero words.
> The first edition indirect blocks were a bit different though: if the
> file was bigger than 8 blocks (4kB), all the blocks in the inode were
> (singly) indirect.
> -- Richard
> -- 
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.

  reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-11  2:37 Erik E. Fair
2019-04-11  5:28 ` Ronald Natalie
2019-04-11 15:57 Richard Tobin
2019-04-11 19:09 ` William Corcoran [this message]
2019-04-11 19:49 ` Bakul Shah

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