Text 618, 43 rader
Skriven 2012-07-14 12:05:19 av Andrew Leary (1:320/119)
    Kommentar till text 114 av mark lewis (1:3634/12.0)
Ärende: .fidonet
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Hello mark!

Monday July 09 2012 13:40, mark lewis wrote to Robert Bashe:

 ml> yes, the HMB format does have some limitations but these are easily
 ml> worked with as long as one doesn't attempt to maintain a huge live
 ml> message base with it...

 ml> 255 message areas

QuickBBS only allowed 200 areas, and other programs that adopted HMB maintained
that limit for compatibility.  Technically, there is no reason that HMB
couldn't have 255 areas, or even 256 if you use 0.

 ml> 65534 maximum messages across ALL areas, not per area

32767.  For some unknown reason, Adam Hudson used a signed integer for the
message number.

 ml> 1Gig maximum file size for the message body storage file

16MB was/is the maximum for MSGTXT.BBS.  MSGTXT.BBS is a file of 255 byte
records; the index into that file is a 16-bit integer, with a maximum value of
65535. Thus, MSGTXT.BBS cannot exceed 16711425 bytes without becoming corrupted
and crosslinking messages.  Once this happens, the only fix is to DEL MSG*.BBS
and start over.

 ml> those are the main ones that i recall from scanning over the HMB specs
 ml> real quickly... at least two sets of problems are similar in that they
 ml> are "rollover" problems with the counters used... both will lead to
 ml> message corruption... another developer created a HMB similar format
 ml> called Goldbase which it really the HMB with larger counters... it has
 ml> similar limits and problems but they are not triggered until a much
 ml> larger count is achieved... then there are/were other formats that
 ml> were basically multiple HMBs... in this way, each base held messages
 ml> for only one area... the other limitations were still in place...

A database per area scheme such as JAM or Squish is much more efficient.

Andrew

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