[Discuss] Versioning File Systems

[shankar.viswan at gmail.com (Shankar Viswanathan)]

On Fri, May 4, 2012 at 5:10 PM, MBR <mbr at arlsoft.com> wrote:
> Other operating systems in existence at the time Unix was being designed
> required you to call different system calls depending on what device you
> were trying to do I/O to.? And some operating systems knew about file types
> and defined the complete set of file types you could deal with - e.g. source
> code, object files, linked executable, etc.? If you wanted a new file type,
> you had to get the people who provided the operating system (usually the
> hardware vendor) to add it in the next rev of the OS.? This created all
> sorts of problems.
>
> To try to solve those problems, Thompson, Ritchie, etc. settled on the
> philosophy that, to the greatest extent possible, all Unix I/O would be
> treated as nothing more than a stream of bytes, with no structure imposed on
> it by the operating system.? So, device drivers in the kernel try to make
> files in the filesystem and devices that can only do output (e.g. a
> printer), etc., look the same to code in the application layer.? The
> philosophy that only applications should impose structure on the data, and
> that the kernel should always present I/O as an undifferentiated byte stream
> is one of the things that made Unix such a success.? Versioning filesystems
> run very much counter to the traditional Unix design philosophy.
>
> Mark Rosenthal

Mark,

Your reasoning makes a lot of sense in the context of Unix philosophy.
Thanks for this explanation.

-Shankar