> A colleague said, "Everything is a file." OS/360 aimed for that > target with the abstraction of DD names, but missed by exposing > hardware characteristics with "attributes" such as RECFM=FBM.
That was not an OS/360 design goal, but I don't believe that there is any conflict between attributes and "everything is a file" and, in fact, Unix has attributes. Where OS/360 falls short of that non-goal is that there is not a uniform naming system for "everything"; it's UNIT=foo instead of something like DSN=DEV.foo. I would not classify RECFM as device dependent, but I would agree that, e.g., SPACE is, at least partially. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of Paul Gilmartin [0000042bfe9c879d-dmarc-requ...@listserv.ua.edu] Sent: Saturday, July 29, 2023 8:50 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: speaking of filesystems [was: Definition of mainframe?] On Sat, 29 Jul 2023 18:26:29 -0400, Rick Troth wrote: > >Here's a neat trick: you can make a hard link to a sym-link. > I believe that's not required for POSIX conformance. But I may be misled by the lack of that ability in the "ln" utility. >There are only a handful of actual file *types*: > > * plain file > * directory > * character special (like a terminal) > * block special (like a disk drive or partition thereof) > * symbolic link > * and a couple others added by OMVS ... really > A colleague said, "Everything is a file." OS/360 aimed for that target with the abstraction of DD names, but missed by exposing hardware characteristics with "attributes" such as RECFM=FBM. OMVS recovered considerable with access methods that generate RDWs, etc. as specified by the DCB. (But they don't synthesize the carriage control character. ) CMS doesn't even try, having distinct system calls for each device type. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
