On Tue 01 Jan 2013 at 16:34:55 +0100, firstname.lastname@example.org wrote: > > On 2012-09-24, at 20:40, Spiro Trikaliotis wrote: > > > The 154x and 157x drives can handle up to 3 simultaneous open files > > (except the directory), with one exception: A relative file counts for > > two files, making it one relative file and one sequential ("normal") > > file only. > > How does one check which channels are in use? For sequential one can > read the SAT table, which should show the (ORed with $60 - why?) sec > address aka channel but what about REL? Is there a reliable method for > deriving number and numbers of channels already in use? I can't quickly find my copy of Inside Commodore DOS, but there is probably a table mapping secondary addresses to channels and channels to buffers, or something like that. Another way to find out if a specific buffer is free, is to try to open it: open 1,8,sa,"#2" to check buffer 2. Maybe that would be a way to find out what you want to know? Ah, BUF0 and BUF1 (00A7-D resp. 00AE-F4) are each explained as "Table of channel #'s assigned to each of the buffers. $FF is inactive buffer", although a note in the margin says "LINDX -> buf#" which contradicts that. (A Logical INDeX is a sort of DOS-internal file number). The note makes more sense because there are indeed sometimes two buffers assigned to a LINDX. $022B-3D LINTAB maps secondary addresses to a status: $FF is inactive, other values are read, write, or read/write. -Olaf. -- ___ Olaf 'Rhialto' Seibert -- The Doctor: No, 'eureka' is Greek for \X/ rhialto/at/xs4all.nl -- 'this bath is too hot.' Message was sent through the cbm-hackers mailing listReceived on 2013-01-02 01:00:03
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