[sane-devel] SaneTwain and HP2200C

Martyn Ranyard ranyardm@lineone.net
Wed, 14 Aug 2002 10:29:39 +0100

Hi all,

   I have a scanner attached to a server (HP 2200C attached to a Linux Dell 
Server (Slackware 8.1), and the plustek backend seems to have some strange 
issues (especially with sanetwain).

   1.  The Scanner takes approx 40s to warm up the lamp, before it does 
anything - e.g. hit the preview button, wiat 50 secs, start receiving data, 
draw your box, hit the scan button, wait 50 secs, start receiving data.  Is 
there really no way of receiving the temperature of the lamp, and not just 
switch it on and wait a pre-specified amount of time?

   2. When propogated over the network, the scanner does scan, but the 
delay mentioned means that sanetwain just is not usable,  I think because 
of a network timeout waiting for data.  I can see several solutions to 
this, and will elucidate on the easy option and what I consider to be the 
Good (TM) option :

   a. (easy option) alter sanetwain to increase the timeout value
   b. (Good(tm) option) add to the network (and backend) protocol so that 
when the backend is waiting for something, it can be pinged (in the IP 
sense), to check it hasn't hanged.  This probably involves lots of work, 
but would mean that the front ends could give a better clue as to what is 
happening - and maybe a status message could be passed (In this case "Lamp 
warming up") so that the user knows that the program hasn't locked 
up.  Because this would change the protocol, sanetwain would have to be 
updated, and the network timeout would not be a problem (send ping packet, 
recieve pong packet).

Okay, so thats my 2p worth, lets hear what other people think - and yes, 
you can flame me for offering design criticisms without offering to do any 
coding, but my skills at the coding level lie within the confines of 
Pascal, and not within networking (although I am getting better at it, it 
still foxes me sometimes).

Martyn Ranyard
Free Software Advocate

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