[ql-users] Running out of memory gracefully
I thought this my interest the Group - Original Message - From: "Ian Bruntlett" [EMAIL PROTECTED] To: "Richard Downer" [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Thursday, September 11, 2003 6:17 PM Subject: Re: [edlug] Running out of memory gracefully. Hi Richard, On Monday 08 September 2003 11:09 pm, Richard Downer wrote: I'm feeling in a technical mood. I'll have a go at answering this. [snip] Linux does "overcommit" on memory. This is because the amount of "free memory" available is not as easy to calculate as you might think. Linux has a feature called shared copy-on-write memory. It's used when implementing the fork() system call. What fork() does is take the current process and make a (near) exact copy of it -- including all of its memory. Now to actually do a byte-for-byte copy of all of a process's address space will be slow, so Linux doesn't do it. Instead it marks the processes memory pages as shared copy-on-write. Both processes share the same memory pages. This is fine as long as they are both doing reading only. As soon as either process writes to the shared memory, only then is a copy made. This gives the illusion that each process has its own copy of the original memory space, when in fact much of it can be shared. fork() is interesting but I propose that job creation be handled differently. I used a system on the Sinclair QL called Qdos (later called Minerva, SMS2) and it had kernel calls to allocate space in the transient jobs area IIRC and to creat a job. Instead of having fork() exec() I propose that there be a variant of exec that creates another process and loading the job from file into that process. The need for fancy VM work is removed. OTOH fork() is probably implemented using VM pointer manipulation and is probably very cheap. Maybe my idea is not needed. [snip over commit explanation] Having said all that, if your system runs out of memory, a NULL from malloc() is probably the least of your problems. How can you fix the problem if the system is swapping like crazy and there's no memory to start a shell? That's not very graceful ;-) A NULL from malloc (or a C++ exception from new) is not a problem. In fact its one way a well behaved Unix program can go "ok I've run out of memory, I'll free up some space and return to a sensible state". I *want* malloc to return NULL if the system has run out of memory - its part of its standardised behaviour and all sorts of programs (including daemons) would do well to make proper use of it. Ian - -- You can find the EdLUG mailing list FAQ list at: http://www.edlug.org.uk/list_faq.html
[ql-users] elvis
HI I recompiled elvis and got it allmost working on my Q40. I go forward now to port VIM.
Re: [ql-users] Rogue page (plus some teasers re QWord)
Now there you should *REALLY* be using PNGs which are far better than GIFs (and they're not covered by an insane Patent either) As for your scanner it's because you failed to Deposit 1 into the slot to your right. Funds will be wired directly to Digital Precision Ltd. offshore accounts - Fear not, no record of the transaction will ever exist ;-) In all seriousness now... he couldn't be that bad now could he? Oh yes, I forgot about PNGs, yes I could use them too. As for scanning Freddy's picture...he probably did as much damage to my scanner as to my phone bill when we talked years ago in DP/DJC days ;-)) (Only joking of course) The real reason for the failure of my scanner (you can tell I was up half the night with this, about the only time round here when my nuisance DIY neighbour isn't banging hammering and drilling something and I can actually *CONCENTRATE*) was the fact that the arms on which the scanner head moves had gone dry and dirty, so the gear mechanism (little plastic cogs and a belt like a caterpiller track) were slipping. Stole some of my wife's Vaseline (she uses it for dry lips in case anyone asks) and gently cleaned and lubricated the tracks and it's now able to scan about 2/3 of an A4 page until it gets to the part of one cog where a tooth has broken off then the scan head stops or slips out of sync. Look out guys...found some more pics. And after judicious application of Tony Tebby's chemistry set, came up with an alternative picture of him...patience! Fear grips the QL community...an evil person is on the loose...whose picture will appear on the Rogues Gallery next :-) (OK, at least it stirred up some discussion and created a little bit of fun!) -- Dilwyn Jones
Re: [ql-users] elvis
In message [EMAIL PROTECTED], Michael Grunditz [EMAIL PROTECTED] writes I recompiled elvis and got it allmost working on my Q40. I go forward now to port VIM. I hope that you are successful with the work. On an amusing front ... 'Elvis' is known in England to be working down at the local chip shop ( fast food outlet ), ... and 'VIM' is a powerful cleaning agent that comes in the form of a white powder :-) -- Malcolm Cadman
Re: [ql-users] The List
In message [EMAIL PROTECTED], =?iso-8859-7?B?IlBob2VidXMgUi4gRG9rb3MgKNbv3+Lv8iDRLiDN9Pzq7/IpIg==?= [EMAIL PROTECTED] writes On Fri, 12 Sep 2003 21:57:45 +0100, Malcolm Cadman [EMAIL PROTECTED] wrote: In message [EMAIL PROTECTED], [EMAIL PROTECTED] writes Is the list working today?? Strangely quiet and one message I sent certainly hasn't come back Could just be your broadband playing up :-) Must be the running AOL man ;-) It probably bypassed it :-) In all fairness though and to repeat my previous rant something needs to be done with the quanta list server Yes, I was just being slightly envious of the broadband :-) -- Malcolm Cadman
[ql-users] Berchtesgaden (2003-10-04)
Hello :) Just a question : May there be some traders at the QL-show in Berchtesgaden, the 4th of october, selling any Q60 for carry ? CU :)
Re: [ql-users] elvis
On Sat, 13 Sep 2003 11:59:41 +0100, Malcolm Cadman [EMAIL PROTECTED] wrote: In message [EMAIL PROTECTED], Michael Grunditz [EMAIL PROTECTED] writes I recompiled elvis and got it allmost working on my Q40. I go forward now to port VIM. I hope that you are successful with the work. On an amusing front ... 'Elvis' is known in England to be working down at the local chip shop ( fast food outlet ), ... and 'VIM' is a powerful cleaning agent that comes in the form of a white powder :-) An elvis port already exists. Go to Dave Walker's site and get it... Phoebus -- Visit the QL-FAQ at: http://www.dokos-gr.net/ql/faq/ (Still uploading stuff!) Visit the uQLX-win32 homepage at: http://www.dokos-gr.net/ql/uqlx.html Visit the uQLX-mac home page at:http://www.dokos-gr.net/ql/uqlxmac.html
[ql-users] From Rich Mellor
I've been asked by Rich Mellor to send this to the list as he cannot for some reason send it (resent) When I run QWord on the Aurora without SMSQ/e loaded, I need to make the standard Pointer a blank sprite, using the machine code routine IOP.SWDF (please no suggestions to use any other toolkit) I have tried to follow p66 in the QPTR manual, although I see that the description of the call does not actually specify that a1 needs to be set to the subw_table !! My code is as follows (with the correct QDOS window channel ID in A0, pointing to a managed window ouline): * Change the window pointer to null pointer move.ld4,-(a7) lea subw_defn,a1Set up table of sub-windows lea subw_table,a4 move.la1,(a4) lea sprite_ptr,a4 Set up sub window sprite pointer lea blank_sprite,a1 move.la1,(a4) moveq #$7d,d0 Set up new sub-windoow definition moveq #-1,d3 with a blank pointer lea subw_table,a1 trap #3 move.l(a7)+,d4 * more code follows.. CUT subw_table dc.l 0 dc.l 0 subw_defn dc.w 512 Window X Size in pixels dc.w 480 Window Y size in pixels dc.w 0 X origin dc.w 0 Y origin dc.w 0 attributes - spare dc.w 0 border width dc.w 0 border colour dc.w 0 paper colour sprite_ptr dc.l 0 Pointer to pointer sprite for window blank_sprite dc.w 1,0 dc.w 1,1 dc.w 0,0 dc.l col_patt-* dc.l patt_mask-* dc.l 0 col_patt dc.l 0 patt_mask dc.l 0 However, the sprite still seems to be there (if only one or two pixels big) . Where have I gone wrong?? Maybe it's because I am using direct hardware access to the Aurora screen, but I doubt it -- Rich Mellor RWAP Services 35 Chantry Croft, Kinsley, Pontefract, West Yorkshire, WF9 5JH TEL: 01977 610509 Visit our website at: URL:http://hometown.aol.co.uk/RWAPSoftware Stuck with ordinary dial up internet connection ?? Read our review of internet accelerators and broadband at: URL:http://hometown.aol.co.uk/RWAPSoftware/reviews.html
Re: [ql-users] Rogue page (plus some teasers re QWord)
In message [EMAIL PROTECTED], Dilwyn Jones [EMAIL PROTECTED] writes snip the arms on which the scanner head moves had gone dry and dirty, so the gear mechanism (little plastic cogs and a belt like a caterpiller track) were slipping. Stole some of my wife's Vaseline (she uses it for dry lips in case anyone asks) This reminds me of a joke - it should go in ql-chat really but it is quiet in here so. 1st woman : 'I saw him in the chemist - he was buying Vaseline' 2nd woman : 'What does he use that for?' 1st woman : 'Sexual purposes' 2nd woman: ' Sexual purposes?' 1st woman: 'Yes - he smears it on the door knob - keeps the kids out!' -- Roy Wood Q Branch. 20 Locks Hill, Portslade, Sussex. Tel: +44 (0) 1273 386030fax: +44 (0) 1273 430501 web : www.qbranch.demon.co.uk
Re: [ql-users] Berchtesgaden (2003-10-04)
Hi Gerhard, I'll be there but I won't have a Q60 for sale. Maybe you should ask Peter or DD directly if they can arrange something for you. Cheers Jochen Gerhard Plavec wrote: Hello :) Just a question : May there be some traders at the QL-show in Berchtesgaden, the 4th of october, selling any Q60 for carry ? CU :) -- Jochen Merz - Im stillen Winkel 12 - D-47169 Duisburg Tel. +49-(0)203-502011 - Fax +49-(0)203-502012
Re: Re: [ql-users] Rogue page (plus some teasers re QWord)
Somehow reminds me of the quip I child-proofed my house--but they keep getting in! Even if it isn't sexual in nature. And there are other jokes ... Doug LaVerne Oak Ridge, TN, USA From: Roy wood [EMAIL PROTECTED] Date: 2003/09/13 Sat PM 12:49:49 EDT To: [EMAIL PROTECTED] Subject: Re: [ql-users] Rogue page (plus some teasers re QWord) In message [EMAIL PROTECTED], Dilwyn Jones [EMAIL PROTECTED] writes snip the arms on which the scanner head moves had gone dry and dirty, so the gear mechanism (little plastic cogs and a belt like a caterpiller track) were slipping. Stole some of my wife's Vaseline (she uses it for dry lips in case anyone asks) This reminds me of a joke - it should go in ql-chat really but it is quiet in here so. 1st woman : 'I saw him in the chemist - he was buying Vaseline' 2nd woman : 'What does he use that for?' 1st woman : 'Sexual purposes' 2nd woman: ' Sexual purposes?' 1st woman: 'Yes - he smears it on the door knob - keeps the kids out!' -- Roy Wood Q Branch. 20 Locks Hill, Portslade, Sussex. Tel: +44 (0) 1273 386030fax: +44 (0) 1273 430501 web : www.qbranch.demon.co.uk
