[TUHS] File-as-record

[TUHS] File-as-record

[Doug McIlroy]

> On the programming side, there wasn't either the memory capacity or
> processing power to implement a modern disk file system.  One of the
> first computers I worked with was a System/360 model 25 running
> DOS/360.  The machine had 48K of core memory, 12K of which was for the
> OS, leaving 36K for programs.  No virtual memory.

Unix was a counterexample. Recall that v1 worked on a 24K
machine, 16K of which was OS and 8K user. And it had a modern
file system. Programming was so much easier that it lured
people (e.g. me) away from big mainframe computers.

Doug

[TUHS] Happy birthday, Dennis Ritchie!

[Dave Horsfall]

Sadly no longer with us (he exited in 2011), he was forked in 1941.  Just 
think, if it wasn't for him and Ken, we'd all be running Windoze, and 
thinking it's wonderful.

A Unix bigot through and through, I remain,

-- 
Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."

[TUHS] Happy birthday, Dennis Ritchie!

[Noel Chiappa]

    > From: Dave Horsfall <dave at horsfall.org>

    > Just think, if it wasn't for him and Ken, we'd all be running Windoze,
    > and thinking it's wonderful.

It's actually worse than that.

We'd be running a Windows even worse than current Windows (which has managed
to pick up a few decent ideas from places like Unix).

	Noel

[TUHS] Happy birthday, Dennis Ritchie!

[Michael Kjörling]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 537 bytes --]

On 8 Sep 2017 17:04 -0400, from jnc at mercury.lcs.mit.edu (Noel Chiappa):
> We'd be running a Windows even worse than current Windows (which has managed
> to pick up a few decent ideas from places like Unix).

Like directories, and free-form files (collections of bytes as opposed
to collections of records)?

-- 
Michael Kjörling • https://michael.kjorling.se • michael at kjorling.se
                 “People who think they know everything really annoy
                 those of us who know we don’t.” (Bjarne Stroustrup)

[TUHS] Happy birthday, Dennis Ritchie!

[Wesley Parish]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1444 bytes --]

'fraid so. The Unix directory structure and the correlating free-form file competed with the file-as-
record-structure and directory-as-record-structure in the seventies and eighties. The competition had 
finished by the nineties, and hardly anybody remembers it now.

Seriously, how many grandmothers can you think of who would know how to allocate disk space for a 
photo of their grandkids? Who would be able to guess how many bytes a letter might take up?

Free-form files and directory nodes (with the corresponding requirement that the OS know how to 
allocate and reallocate disk space) helped democratize computing.

Just my 0.02c :)

Wesley Parish

Quoting Michael Kjörling <michael at kjorling.se>:

> On 8 Sep 2017 17:04 -0400, from jnc at mercury.lcs.mit.edu (Noel Chiappa):
> > We'd be running a Windows even worse than current Windows (which has
> managed
> > to pick up a few decent ideas from places like Unix).
> 
> Like directories, and free-form files (collections of bytes as opposed
> to collections of records)?
> 
> -- 
> Michael Kjörling • https://michael.kjorling.se •
> michael at kjorling.se
>  “People who think they know everything really annoy
>  those of us who know we don’t.” (Bjarne Stroustrup)
>  



"I have supposed that he who buys a Method means to learn it." - Ferdinand Sor,
Method for Guitar

"A verbal contract isn't worth the paper it's written on." -- Samuel Goldwyn

[TUHS] File-as-record (was: Happy birthday, Dennis Ritchie!)

[Greg 'groggy' Lehey]

On Saturday,  9 September 2017 at 13:16:30 +1200, Wesley Parish wrote:
> 'fraid so. The Unix directory structure and the correlating
> free-form file competed with the file-as- record-structure and
> directory-as-record-structure in the seventies and eighties. The
> competition had finished by the nineties, and hardly anybody
> remembers it now.

Sorry, I don't understand this.  Can you give an example of
file-as-record and directory-as-record?  Some of it suggests MVS, but
not quite.

Greg
--
Sent from my desktop computer.
Finger grog at lemis.com for PGP public key.
See complete headers for address and phone numbers.
This message is digitally signed.  If your Microsoft mail program
reports problems, please read http://lemis.com/broken-MUA
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 163 bytes
Desc: not available
URL: <http://minnie.tuhs.org/pipermail/tuhs/attachments/20170909/b9b9966f/attachment.sig>

[TUHS] File-as-record (was: Happy birthday, Dennis Ritchie!)

[Wesley Parish]

I picked up a book in the early nineties called File Structures or File Systems: I've forgotten which, 
because I didn't read it as much as I had intended. It covered the IBM MVS mainframe dataset file and 
directory structure and the Unix file and directory structure. And yes, I was referring to the MVS dataset, 
as much of it as I can remember from that book. (I sorry I can't recall the exact title: the book is 
somewhere at the bottom of a pile of other books from my last move several years ago.)

Wesley Parish

Quoting Greg 'groggy' Lehey <grog at lemis.com>:

> On Saturday, 9 September 2017 at 13:16:30 +1200, Wesley Parish wrote:
> > 'fraid so. The Unix directory structure and the correlating
> > free-form file competed with the file-as- record-structure and
> > directory-as-record-structure in the seventies and eighties. The
> > competition had finished by the nineties, and hardly anybody
> > remembers it now.
> 
> Sorry, I don't understand this. Can you give an example of
> file-as-record and directory-as-record? Some of it suggests MVS, but
> not quite.
> 
> Greg
> --
> Sent from my desktop computer.
> Finger grog at lemis.com for PGP public key.
> See complete headers for address and phone numbers.
> This message is digitally signed. If your Microsoft mail program
> reports problems, please read http://lemis.com/broken-MUA
>  



"I have supposed that he who buys a Method means to learn it." - Ferdinand Sor,
Method for Guitar

"A verbal contract isn't worth the paper it's written on." -- Samuel Goldwyn

[TUHS] File-as-record

[Arthur Krewat]

Not sure I quite get this "file as record" thing.

On TOPS-10, you create a file, edit a file, you don't have to allocate 
space for it before you use it.

Sure, it's made up of "blocks" - and writing to the file requires you to 
do it in blocks. But allocating those blocks was done on as the fly as 
you wrote to it.

Also, the first thing I did was to make my own routines that would allow 
the program to read/write in random-size chunks, blocking as it needs to.

Is the distrinction that the operating system (libraries) allowed you to 
read/write random size chunks? If so, the underlying structure of a UNIX 
filesystem still required block I/O. It was just hidden from the 
programmer.

But for peak performance, you still needed to do things in big enough 
chunks (blocks).

If I had known that random-size chunk read/writes were a "thing" I would 
have added it to the TOPS-10 monitor sources and submitted it back to DEC :)

AAK

PS: First TOPS-10 monitor was 1964