Path: utzoo!utgpu!water!watmath!clyde!rutgers!ucla-cs!zen!cory.Berkeley.EDU!kolding
From: kolding@cory.Berkeley.EDU (Eric Koldinger)
Newsgroups: comp.os.misc
Subject: Re: OS features
Message-ID: <5360@zen.berkeley.edu>
Date: 17 Dec 87 18:51:48 GMT
References: <561@amethyst.ma.arizona.edu> <3228@tut.cis.ohio-state.edu>
Sender: news@zen.berkeley.edu
Reply-To: kolding@cory.Berkeley.EDU.UUCP (Eric Koldinger)
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Organization: University of California, Berkeley
Lines: 31

In article <3228@tut.cis.ohio-state.edu> karl@mumble.cis.ohio-state.edu (Karl Kleinpaste) writes:
>	One of the features of AOS/VS (Data General) that I like is its
>   variable element size. Files are made up of elements of a given number
>   of blocks. For example, if a file's element size is 10 blocks, the file
>   will grow in chunks of 10 blocks at a time...
>   ...I haven't seen this feature
>   on any other operating system. Has anyone else?
>
>Computer Consoles, Inc's PERPOS of a couple of years back supported
>contiguous file creation.  You had to give it the total size of the
>file required, as I recall, no file growth once it's created.  PERPOS
>(a fault-tolerant UNIX derivative) was intended for a heavy
>transaction-oriented system, which made this sort of use important.

OS/360/370/SVS/MVS had this feature beat by years.  When you create a file,
a painful process at best, you specify ALL of it's attributes, such as
logical record length, block size (yes, you set it yourself, not the system),
whether or not records are of variable size, and the amount of space the
file will take up.  It even allows for a somewhat limited expansion of the
file by allocating secondary extents which are allocated when the primary
extent is filled up.  However, you can only get 15 secondary extents and 1
primary one, so files can't grow forever, but with utilities the extents
can be merged to allow more growth, but again this is a painful process (seems
everything in MVS is painful, but maybe I just like Un*x too much).

[Eat hot death line-counting scum!]

		_   /|				Eric
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