Re: ancient OS history, ARM is sort of channeling the IBM 360

According to Scott Lurndal <slp53@pacbell.net>:

There still is additional overhead.  But the application amd
programming language mix has changed, so stream oriented I/O is now the
default.

>
Is there?   It's trivially easy to impose a record structure
on a stream of bytes, and all the unix file access APIs allow
direct access to the device without extra buffering if desired,
subject to some alignment constraints.

At the time Unix was written, the big advanage of byte stream text was
that there weren't any trailing blanks so you fit a lot more data onto
a disk than you did with 80 or 132 character fixed records. I realize
that mainframe disk files can have variable length records but it's
not my impression that they were ever very popular.

These days although Unix-ish systems still let you read or write
arbitrary text chunks, in practice everyone uses I/O libraries that do
reads and writes aligned to disk blocks, or map tthe file and let the
pager handle it. The logical file format is an application thing on
top of that.

--
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly