AS/400 File Structure

[TiziteLayinLow]

My instructor asked me to write the comparisons between AS400 and DOS file structures. however I cannot find anything that general about it on google.com


Any ideas are greatly appreciated. Thanks- Matt

 

[drag]

a bit of a tall order if you don't know anything about filing systems.

I know a bit about OS/400, but not much at all. So don't take what I say as gospel, it's far from it.

PC/DOS/Windows/whatever file structures are based on the traditional Unix-style model of having directories and files. You know, the file structure. It's not as nice as Unix stuff, becuase it's not a real directory tree (at least until you get into newer versions of windows), but it's 'root' is based on the physical layout of whatever device you installed it from. (the C: drive, D: drive, or whatever)

But basicly its just files and directories. You have directories inside directories, and those directories contain abitrary files that contain different types of data. ASCII text, binary information, jpeg images, music, whatever.

OS/400 file system is based on a database model. Each file is like a it's own little database object with tables (or the files are like tables in a database, I guess) and columns and rows and such and the entire system, the files, and everything in it, is cross referenced and relational. Basicly one big relational database. The divisions between different 'areas' of the filing system are called 'libraries'. And that's how you would seperate things. Say each user, or each type of user, would have their own library that they'd use for their space and have certain rights to other libraries.


That should get you started.
(best bet for you, I am thinking, is to head on down to the library and find a book on OS/400 or as400 programming or administration.)

 

[Lovehandles]

Drag,

I never did learn much about AS/400 systems. So is an AS/400 a type of server and OS both wrapped up into one?

 

[drag]

AS/400 is the server, and OS/400 is the type of operating system that runs it... I don't know much about it, took a class on OS/400 and talked to my boss a bit about it. (he previously worked with AS/400 machines in a different job, right now we are using s/390, not that I am a expert on that either by any means)

You have different OSes on a AS/400. For example you can install AIX on it or Linux on it. But typically when they say 'AS/400', they mean 'OS/400' is running it.

Now I don't think they even call it as400 anymore. At least not to much, IBM tends to use terms interchangably. They are like the eserver ISeries Midrange servers.

IBM's terms tend to get f**ked up pretty readidly. For instance IBM doesn't have much of a distinction between POWER vs PowerPC anymore and use the terms interchangably in some documents. It's now the 'Power archatecture' were those are just subsystems.. http://www-03.ibm.com/technology/power/

Used to be you have AS400 running OS/400, now they call it ESeries midrange servers running i5/OS (also called V5R4) or ESeries running OS/400 (also called V5R3) and they'll mix and match depending on when a paticular peice of documentation was written.