The unity of Unix

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Yes, UNIX has the right philosophy...: One central tenet of Unix is that every device is treated as a sequential stream of bytes.

This is a tremendously useful approach. There are no obscure, low-level, API's. No NDIS, no Win32 kernel hackery. If you want to access a device (say a tapedrive or a sound card), you just open a file. It's so simple it's brilliant! This makes life for app developers who consume these device services sooooooo much easier than mucking with an API. BTW - there are "character" devices which are streams and there are "block" devices that can be accessed radomly.

However, in practice we often want to access devices randomly.

Really? You want to access a sound stream randomly? We're talking about devices here. You never want to seek randomly though a soundcard... That doesn't even make sense. You just send a stream of sound data to the sound card (which is a file - /dev/dsp to be exact).

It was possible to map exactly where a character would appear on the screen. I think we can agree that all end user programs require this kind of approach. Yet if you want to address the terminal randomly in this way in Unix there is no standard way of doing it. Every program has to do this itself (vi being a case in point).

Incorrect. Look up the ncurses library. Random access to the terminal is easy and done often by many apps.

With data the matter of random access becomes even more pressing and in particular random access that takes account of the logical rather than physical structure of the data. Again Unix offers no support in this area.

Really? So when I open a file in random mode on UNIX, it's just my imagination? Dude, get it through your head - UNIX has supported random access since its inception. If you're talking about pipes, then yes they are sequencial. Look up "shared memory" sometime and get your facts straight.

It thus seems to me that the systems software is actually more "open" than the operating systems it sits on top of.

A compatible protocol between platforms does mitigate the major compatabily problems, but consider the fact that Oracle had to re-write their database software for VMS, Windows, and UNIX. Note that the Oracle code base for the UNIX version can be recompiled for Solaris, Linux, AIX, HP-UX, and others *NIX with little or no changes. The Windows version however requires major changes and wacky inconsistent code.

Having used Unix for a number of years I still think that the main reasons for its success are its portability and its cheapness, rather than any inherent qualities of the operating system itself.

I disagree. Having used Windows and UNIX for years (and yes, I DO have my MCSE), I think that there is a major simplicity dividend you gain with UNIX. UNIX is simple. Everything is a file. The kernel is simple. Permissions are simple. Managing processes is simple. Scheduling tasks is simple. Writing shell scripts is simple (it's just like using the shell directly) -- thus automating tasks is simple.

Due to the simplistic nature there are other bennefits:
* It's easier to keep secure. There are fewer moving parts. There isn't a process I can't kill, nor a port I can't lock down. In Windows, there are services and ports that can NEVER be turned off.
* It's easier to optimize.
* It's easier to develop apps for: Shell, Perl, Python, Java, C/C++. There are many options. It's a developers paradise.
* I actually has an optimistic locking file system. When one file is opened by an app, you can still read that file from another app. Try opening an Excel spreadsheet on Windows twice.

I could seriously go on and on and on, but I'll keep this post short.

UNIX/Linux is a great platform, and in my optinion, far superior to Windows -- especially as a server.

-Bryan; Posted by: prime21 Posted on: 07/27/05 You are currently: a Guest | Members login | Terms of Use