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| Greg's diary |
| January 2005 |
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| Saturday, 1 January 2005 | Echunga | Images for 1 January 2005 |
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And another new year! The Millennium is 0.5% over already!
In the afternoon to the wedding of Martine and Peter Stibbs. Nice ceremony and reception, with some photos. Unfortunately, problems at home showed up, and we had to leave early. Not the best start to the new year.
| Sunday, 2 January 2005 | Echunga | Images for 2 January 2005 |
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Fifth hackers' barbecue today; this is becoming quite a tradition. Today we had Daniel O'Connor (as always) with his wife Fiona, Berndt Wulf and Chris Yeoh. New were Dale Long and (briefly) Ben Elliston and his wife Lisa, who came in basically to take a look and go again.
Every barbecue is different; this time was marked at least by fewer photos . Also spent some time talking about infrared receivers. Daniel brought a kit that had built a while ago, but (strangely) it only recognized some of the codes generated by the Philips remote control that I wanted to use. Chris wrote a program for TiVo some time ago, mainly intended to help the TiVo send commands to foreign VCRs, but it should also be able to help us identify what the difference is with the “dead” keys.
| Monday, 3 January 2005 | Echunga | |
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Brew day again today. It's still taking too long, but it's no longer as much stress. Got started early, so I was also finished relatively early.
Essey Deayton held a barbecue today, the last one now: she's moving to Queensland. It's sad to see her go, but maybe that's a bright side to it; like Assurancetourix in the Astérix stories, she has the ability to attract bad weather. Last time we had such a storm the we can still see the results on the water tank; today, just before the barbecue, we had another storm and 13 mm rain, enough to interrupt my satellite reception several times:
Jan 3 12:06:26 sat-gw sm200d[20817]: Tuner +*** TunerLock Jan 3 12:06:28 sat-gw sm200d[20817]: Tuner ++++ Running UP Jan 3 12:06:42 sat-gw sm200d[20817]: Tuner +*** TunerLock Jan 3 12:06:50 sat-gw sm200d[20817]: Tuner **** No signal Jan 3 12:07:12 sat-gw sm200d[20817]: Tuner ++++ Running UP Jan 3 15:19:17 sat-gw sm200d[20817]: Tuner +*** TunerLock Jan 3 15:19:26 sat-gw sm200d[20817]: Tuner **** No signal Jan 3 15:19:39 sat-gw sm200d[20817]: Tuner ++++ Running UP
I also lost modem connections a couple of times, though it's difficult to blame that on the weather unless we're about to see yet another telephone cable failure.
| Tuesday, 4 January 2005 | Echunga | |
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Back to work, and more mail to read and correct. I seem to be spending all of my time responding to mail; I've been planning to do some profiling for nearly 2 weeks now (admittedly, much of it holidays), and I still haven't got round to doing so.
Having to correct mail messages is a pain, and I spent some time working on a document Communicating with email. It's only a start, but hopefully it'll come good soon (after which this link will automatically be updated).
One of the issues was completing the Fedora Core 3 installation that has been dragging on for days. After reading the man pages for rpm and yum and a HOWTO for rpm, it was still not clear to me how to find out what packages I needed to install to do software development.
On FreeBSD I'd fire up fire up sysinstall and get a list by category of what's available, along with a one-liner stating what it is. The best I could find on the Fedora CDs is a directory listing or rpm -qa, which gave me things like:
jwhois-3.2.2-6 libxml2-2.6.14-2 make-3.80-5 irda-utils-0.9.16-3 bind-libs-9.2.4-2 pdksh-5.2.14-30 ftp-0.17-22 gettext-0.14.1-12 rpm-python-4.3.2-21 stunnel-4.05-3
There doesn't seem to be anything corresponding to FreeBSD pkg_info, which at least gives the one-liner. And by comparison, even ls sorts the names alphabetically.
Sent out a message to the Linux SA mailing list and got a number of replies that fell into the following categories:
Tried the last one, and it worked. I don't know if the installer is always so brain-dead, but to install the software development tools I needed to insert 3 CD-Rs a total of 10 times. Well, at any rate, I got it installed. After only 3 days.
| Wednesday, 5 January 2005 | Echunga | |
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So, now I have a functional Linux box, and I can finally start the profiling I wanted to do two weeks ago!
Well, no. In the meantime I was given something else to do, coding for once: set O_DIRECT for a particular file, since it will be read in once and then discarded. That sounded trivial: just change the open flags. Unfortunately, it wasn't that simple: the program uses buffered I/O via a library wrapper, definitely a suboptimal choice. Considered that I might be able to do it anyway by calling fcntl to set the open flags after the return from fopen, but for some reason that didn't work: the flag was set and stayed that way, and there was no error indication, but then it appears that the file returned an immediate end-of-file indication. Using gdb wasn't easy: all this happens in a thread, and my breakpoints didn't stick. I obviously need to RTFM about debugging threaded programs. I was able to put an int3 instruction in the thread and hit it that way, but that's a bit hit and miss.
(Update, 10 January 2005) In fact, it seems that the issues weren't with threading at all; as I had originally expected, recent versions of gdb have no problem with threaded applications. The problem is function renaming. Like other POSIX.1 based systems, Linux provides a function called fopen, and it actually links in a function of that name (so you can set a breakpoint on it), but it's not what it calls:[Switching to Thread -151038272 (LWP 22706)] Breakpoint 3, file_open (p_filename=0x815021c "/fooblah/fooblah/settings.dat", flags=130) at file.c:738 738 handle = fopen(p_filename, "rb");=== gdb -> s755 handle = fopen(p_filename, "ab"); Huh? Where did the call to fopen go?=== gdb -> zs0x0808ee1f 755 handle = fopen(p_filename, "ab"); 0x808ee1f <file_open+663>: call 0x804a0f4 <_init+1608>=== gdb ->0x0804a0f4 in ?? () 0x804a0f4 <_init+1608>: jmp *0x812a2f8=== gdb ->0x0097f050 in fopen64 () from /lib/tls/libc.so.6 0x97f050 <fopen64>: push %ebp=== gdb ->It's also very irritating that the s command doesn't step into the function, so you have to go at the assembler level.
| Thursday, 6 January 2005 | Echunga | |
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More programming today; spent a lot of time confirming that is was really the O_DIRECT flag that was causing fread to (apparently) return an end-of-file indication. So much for that, though I suppose it's understandable: it's a dirty trick to cut in under the library functions. Now I need to rewrite the library to offer the choice of unbuffered I/O.
Yana is leaving for a year in Europe in a couple of weeks, and she wanted to take her ancient Dell Latitude CPi laptop with her. It's done very good service: it's now 7 years old and has a 266 MHz processor and 96 MB of memory, but Yana has never complained. The batteries still seem to be in good condition:
Battery 0:
Battery status: high
Remaining battery life: 83%
Remaining battery time: 3:31:00
I was going to give her my next machine, an Inspiron 7500 built in mid-2000, but that has already had two sets of batteries die on it, the keyboard is falling apart, and the display hinges (which I replaced once in November 2002) appear to be dying again. Instead, decided to get a new machine, and after some discussion on the lists, decided to buy a Dell Inspiron 1150, not too different from adelaide, my Inspiron 5100, on eBay. It seems that the rules have changed since then: at the time I had to have it shipped to the USA (that hasn't changed, presumably because Dell wants it that way), but I could pay with my own non-US funds. That doesn't work any more, and I had to enlist the help of Wes Peters to pay for the thing (and to ship it on to me). Spent quite some time doing that.
The previous paragraph was added on 22 January: this was supposed to be a surprise for Yana.
| Friday, 7 January 2005 | Echunga | |
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On with my code today, and “finished” it by evening. It's gratifying to see both a library and its client compile cleanly after significant changes, but when I came to run it died nonetheless: I had forgotten to change the open flags in the client. By then it was evening, so it'll have to wait until Monday.
Di Saunders along in the afternoon to use the phone. Hers has been out all day, and Telstra have told her that it won't be repaired before Tuesday evening, a clear violation of their Customer Service Guarantee that they didn't even bother to justify. And our federal MP thinks that the penalties for failure to observe the CSG are enough.
Chris Yeardley along in the evening.
| Saturday, 8 January 2005 | Echunga | |
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Exceptionally, did some “work” work this morning: people had been having trouble porting to Linux the code I had written in April last year, and they were doubting that the approach could work at all (conveniently ignoring the results I had shown under FreeBSD), so took a look at it myself.
What a mess Linux system calls are! There are a number which have been paired, such as lseek and lseek64; at least in this case, the latter is designed to handle 64 bit offsets. Now it's true that the name lseek came when they extended offsets from 16 bits (seek), but that's a long time ago and a recognized mistake. Linux goes one step further and hides things so that a call to lseek actually issues a system call lseek64, at least in my case.
Got that sorted out, along with a surprising number of missing functions (lchmod, for example), and got it as far as running before running into trouble. Investigation showed that the system library call open gets bound to a function open64. I have no idea why, but it's really confusing. This also seems to be the real reason why I thought I couldn't debug threaded libraries last week: it wasn't the threads, it was the renamed function. What a mess. Anyway, proved that it can work, so left the rest to Monday.
Essey Deayton along round noon to give Yana an old Kodak DX3215 digital camera. Confirmed that it didn't present a disk-like interface via USB, so off to install gphoto—not for the first time—and ran into the same old problems. There's no man page gphoto(1): after some investigation, discovered it's called gphoto2(1). How I wish that people wouldn't include version numbers in the names of their programs!
gphoto2 is pretty basic, and accessing a digital camera is one of those things where a GUI interface can be of use, so located and installed gtkam, which was able to identify the camera pretty quickly, and sometimes even present the names of the directories on the camera. When I tried to download them, though, all I got was:
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No idea what causes that. Tried it with my Nikon CoolPix 880 with similar results (identified the camera but couldn't access it). The “help” button was no help—literally: somehow it didn't get installed. It seems that every time I install a port I run into problems like this.
Finally out in the afternoon riding with Yvonne, Chris Yeardley and Di Saunders—the first time for three months. Still, Darah behaved herself well, and we had a good time.
| Sunday, 9 January 2005 | Echunga | Images for 9 January 2005 |
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Quiet day, and a good thing too. I've been rotating so much lately that it was difficult to stop. Spent some time doing things like tending to the horse troughs and moving the horses around: gradually the paddocks are becoming overgrazed, and we're going to have to think about what to do there.
| Monday, 10 January 2005 | Echunga | |
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Continued work on the I/O library today, and got things to work for the FILE_UNBUF case, which uses the system call interface instead of C library buffered I/O. The FILE_DIRECT flag (which, in combination with FILE_UNBUF, opens the file with the O_DIRECT flag) didn't work, though. According to the Linux man page:
Under Linux 2.4 transfer sizes, and the alignment of user buffer and file offset must all be multiples of the logical block size of the file system. Under Linux 2.6 alignment to 512-byte boundaries suffices.
This is a problem with Linux only; FreeBSD has no such restriction. On Friday I had done some testing which suggested that this problem didn't even exist, but it bit me here.
It would be easy to just allocate 512 bytes more data and use the first 512 byte boundary as the I/O base, but after going through one instance of doing so, it became clear that we need a way to allocate memory with particular alignment. The most obvious way would be to put a wrapper around the existing membank allocator. But where to store the information? Clearly we need to pass the aligned address to the application, which then frees it at some later time.
One possibility is to store the base address in the block itself (after all, we have 512 bytes to store it in). The exact method isn't so obvious, though: the alignment of the original block could be arbitrary (even with one of the last two address bits set), so it's not clear how to do it right. Didn't come to any conclusion.
My relay board for the sprinkler has arrived. What a nuisance that it requires a 25 pin printer extension cable to connect it. It should have been easy enough to put a 26 pin header on the thing as well, so that it could be mounted inside the computer case and connected internally. That also has the advantage that such cables are readily available.
| Tuesday, 11 January 2005 | Echunga | |
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On with my work today, and finally got my aligned memory allocator working, and then on to test the O_DIRECT I/O. To my surprise got a nearly 10% performance improvement:
User System Elapsed malloced context switches
memory voluntary involuntary
Old (buffered) 451.16 135.19 465 95174 36795 24322
unbuffered 443.87 134.02 459 87654 36528 23685
u+direct 418.46 35.16 428 84240 3641 5410
This shows a minor improvement as the result of the unbuffered I/O (about 1.3%, the order of magnitude that I would have expected), and nearly 10% using the combination of unbuffered I/O and O_DIRECT. This is considerably more than I had expected. Looking at the summary above, it's clear that the big win is in the system code, which is only about 25% of the previous values, and the number of context switches, which is down by up to 90%. I'm assuming that the speed improvement we're seeing is largely a reduction in the CPU time, since my test programs on the same hardware showed almost no difference.
We're not done yet, of course: this is with old hardware. We need to check it again on the Opteron. I'm sure we'll see something very similar, but the performance improvements could be less or more.
| Wednesday, 12 January 2005 | Echunga | |
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Today was punctuated by various problems. They're having some kind of bike race round here, and rumour had it that they had blocked off all the roads round where I live. As a result, Diane couldn't come. Called the police and was told that there was no road block, but it seems that there were people trying to stop the traffic anyway. Yana set off into Adelaide to get some things, and in the process the car overheated, causing further problems. Looks like the cooling fans weren't working at all. Under those circumstances, and given the temperatures today (low 30s) it's surprising that the car didn't overheat earlier, and that she was able to get back to the garage in Echunga.
On the work side, finished off my library functions and stuff; yesterday I made great headway, and today I spent most of the time tidying up, creating a FunnelWeb file for the library shim and committing it. The good news is that subversion is relatively easy (“intuitive”) to use if you know CVS, and the checkin proceeded without difficulty.
| Thursday, 13 January 2005 | Echunga | |
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ICT council meeting today, and I had planned to go into town early and spend the day doing various things. First to Echunga, where I had my hair cut and heard of other people's views on the imposition of the cycle race. The hairdresser will have to close down for tomorrow and Saturday—normally the busiest days of the week—because the cyclists will be blocking access. Like us, she hadn't even been officially informed of the event, let alone offered compensation for lack of income.
That information—dated 17 December 2004—arrived today. I was told that I was only allowed to leave the house under police escort. What arrogance! And that for an event that only took up half the width of the road. Until now I have been neutral about such sporting events, but I'm sure I'm not the only enemy they've made.
Also in the post was a speeding ticket for Yana: on 26 December 2004 she was caught doing 60 km/h in Hahndorf. A year earlier that would not have been an offence. Now they've lowered the speed limit to 50 km/h, not because of any immediate issue, but because they've done it state-wide. As a result, it's suddenly dangerous, and Yana can now pay a fine of over $150.
Admittedly, Australia has a very high incidence of road deaths. That's despite the draconian and often idiotic speed limits. But that's what the police target, not dangerous driving (far too difficult to prove in court). I could drive at 180 km/h down the local South-Eastern freeway on a day with no traffic, and according to the expiation fee schedule, if the police caught me I would be fined $330, given 6 demerit points and would probably lose my license. The same thing in Germany on a freeway with heavy traffic would generally be legal. And where do they have more road deaths? This stupid preoccupation with speed instead of safe driving is particularly ridiculous in a country like Australia with long distances on almost empty roads.
My work took longer than I thought, and I had to cancel my trip to Adelaide. Various changes in the software appear to have negated my performance advantages. Looks like I'll have to finally do the profiling work I've been postponing for weeks.
| Friday, 14 January 2005 | Echunga | |
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First thing this morning there were reports of a SIGSEGV in the program I had been working on, but only on 64 bit machines. Took a look on one and found a bug in exactly the code I had been complaining about on IRC last week: address arithmetic is so complicated that it's almost impossible to do right. In this case I had cast a pointer to an int, but it seems that even on 64 bit machines an int is 32 bits, so I truncated my pointer:
Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 182901467904 (LWP 14754)] mb_alloc_aligned (len=6430760, alignment=512) at mem_aligned.c:126 126 hint->lbyte [7] = 0; (gdb) bt #0 mb_alloc_aligned (len=6430760, alignment=512) at mem_aligned.c:126 ... (gdb) i loc encompass = (ubyte_ *) 0x2a96472038 "" aligned = (ubyte_ *) 0x96472200 <Address 0x96472200 out of bounds>Looking at the code, we had:
ubyte_ *encompass; /* encompassing block */
ubyte_ *aligned; /* and aligned block */
encompass = (ubyte_ *) mb_all (len + alignment); /* allocate memory */
aligned = (ubyte_ *) (((int) encompass + alignment) /* get last address to use */
& ~(alignment - 1));
hint = &((struct basehint *) aligned) [-1]; /* hang off the start */
header_length = aligned - encompass;
This is very ugly code, and I had spent some time wondering how to do it correctly, but I hadn't expected the problems it caused. After some consideration, came to the conclusion that it's safest to use real address arithmetic (in other words, array addressing) as far as possible. Finally replaced the code with:
int offset;
encompass = (ubyte_ *) mb_all (len + alignment); /* allocate memory */
offset = ((int) encompass) & (alignment - 1);
aligned = &encompass [alignment - offset];
hint = &((struct basehint *) aligned) [-1]; /* hang off the start */
Still, there's something basically wrong with address arithmetic in C. It seems that the pedanticism of ANSI C hasn't helped much.
| Saturday, 15 January 2005 | Echunga | |
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Got into the office to discover a large number of people accessing my page about the death of Miss Teak, without accessing the disclaimer page (the link above) first. There are some pretty shocking images on that page, so I decided to prepend them with some more pleasant photos.
In the process, ran into incredible problems with HTML tables. Either the browsers aren't doing what I expect them, or I'm doing something wrong with the markup. In any case, it seems really difficult to get the table at the head of the page to display correctly. It should have my photo on the left, a heading and the date in the middle, and three links on the right. Even when there's enough space, my browsers tend to either wrap one of the lines or not to use the width of the page. And since HTML is in the eye of the beholder, it's impossible for me to know whether it will work properly or not.
While I was pondering this, I saw on IRC:
<brueffer> groogle: how does it feel to get slashdotted? <groogle> brueffer: Relatively painless. <groogle> brueffer: Is it happening again? * groogle notes that sfr is just installing the new machine, so that's unlikely.
It turned out that the answer was “yes”: somebody had posted an article on my temperature control system. It's amazing how the load from a Slashdot posting looks the same every time:
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This is pretty much the same as the T-shirt we had made when Tridge posted his TiVo hacks. Here's David Gibson wearing one:
In this case, though, it suffered a couple of dents where Stephen took down the server for the scheduled replacement. They could have chosen a better time to slashdot me.
| Sunday, 16 January 2005 | Echunga | Images for 16 January 2005 |
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Somehow I didn't get anything done today. Between bottling some beer and tidying up my web pages, I seemed to get through the day without the intended attention to my temperature control software.
I'm now getting regular requests for brewing temperature information, sometimes too regular:
Jan 16 02:09:09 brewer tempcontrol: Query from ip68-10-120-61.hr.hr.cox.net (68.10.120.61) Jan 16 02:09:24 brewer tempcontrol: Query from unknown (195.159.15.218) Jan 16 02:09:56 brewer last message repeated 13 times Jan 16 02:09:59 brewer tempcontrol: Query from unknown (195.159.15.218) Jan 16 02:10:01 brewer tempcontrol: Query from unknown (195.159.15.218) Jan 16 02:10:33 brewer last message repeated 13 times Jan 16 02:10:46 brewer last message repeated 4 times
It seems that the machine at 195.159.15.218 is in some kind of loop. It's not clear whether it's malicious or not, but I firewalled them anyway. In another case, it was much more obvious:
Sent a message to abuse@optonline.net, but of course got neither a reply nor a stop to the attempts. My firewall tells me:
pkts bytes target prot opt in out source destination 5981 239K DROP all -- * * 68.194.48.0/24 0.0.0.0/0 1389 83500 DROP all -- * * 195.159.15.0/24 0.0.0.0/0
| Monday, 17 January 2005 | Echunga | |
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Last week's work left me with an incredible amount of business mail to attend to; that took all day. It's amazing that we're still discovering new requirements at this stage in the product cycle.
| Tuesday, 18 January 2005 | Echunga | |
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Spent some time today considering how to analyse malloc usage. Our software calls it a lot, and the summaries at the end of a run show a surprising divergence in the amount of memory allocated. It would be nice to find a way to analyse the calls. Traditional methods include compiling the code with additional parameters that give file name and line number, but that doesn't help much if there are a couple of other functions in the way.
A better solution would be for the called function to be able to wander down the stack and find the first unknown return address, and then resolve this into file and line number. Spent some time looking at the documentation for BFD, but only came to the renewed conclusion that GNU info is really a pretty terrible documentation system.
| Wednesday, 19 January 2005 | Echunga | |
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Still more work on performance today. Memory allocation is interesting.
Yana's new laptop (a Dell Inspiron 1150) arrived today, and spent some time installing that. It doesn't show FreeBSD up from the best side that the current release (5.3) contains two different tools for resizing Microsoft FAT partitions (obsolete), but doesn't include anything for resizing the standard NTFS partitions. Fortunately, found ntfsresize, the same tool I used on adelaide 18 months ago, on a Knoppix CD-R, but that shouldn't be necessary.
Problems with the laptop in another area too. Unlike adelaide, I was able to start X with no problems, but this time it doesn't recognize the touch pad. Spent some time investigating that, without success.
| Thursday, 20 January 2005 | Echunga | |
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Plenty to do today. Nearly met my next milestone in the program work I'm doing, but had to leave for town, first to an ADUUG lunch at the “Thai in a Wok” in Hindmarsh Square. The weather was good, and we sat outside. I was still feeling peckish after my meal (the obligatory, it would seem, green curry of chicken), so I took a “snack”, their stuffed deboned chicken wings. Excellent; I'd try something like that myself if I had the time. Nice place, but for some reason people left very early, leaving me with some time before my meeting of the ICT council.
To O'Donnel's bookshop, not for the first time, where I saw a book entitled “Beers of the world” or some such, devoting about two-thirds of the 300 odd pages to American beers and only one page to (then) Czechoslovakia. There I read, next to a corresponding emblem “Due to its popularity, the Budweiser brand has become well-known behind the iron curtain”. Decided not to buy the book.
The ICT council meeting was at the Adelaide TAFE, a nice place but not an easy one to find your way around. Many people late as a result, and we had a relatively quiet meeting, in which, however, I found unexpected support for my idea of a South Australian “open source” multimedia project.
Got some replies about how to get the touchpad on Yana's laptop to work: it needs a flag to the psm driver, after which it worked fine:
--- /boot/device.hints 2004/11/05 01:27:17 1.1 +++ /boot/device.hints 2005/01/19 17:36:23 @@ -27,6 +27,8 @@ hint.atkbd.0.irq="1" hint.psm.0.at="atkbdc" hint.psm.0.irq="12" +# Needed on Inspiron 1150 +hint.psm.0.flags="0x1000" hint.vga.0.at="isa" hint.sc.0.at="isa" hint.sc.0.flags="0x100"
This information was from Rob de Graaf. He also states that you need to add entries to /etc/rc.conf, but that's not correct: you just need to remove the entry disabling the mouse.
| Friday, 21 January 2005 | Echunga | |
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More programming today, and discovered that Linux doesn't just require 512 byte aligned buffers (for some strange reason) when performing I/O with O_DIRECT, but the length of the transfer needs to be a multiple of 512 bytes, which is more understandable, but which wasn't clear in my first pass of the man page. Spent a little bit of time thinking about that; there are probably a few tricks we can use.
More work on Yana's laptop. This is just too complicated for non-technical people to install.
| Saturday, 22 January 2005 | Echunga | Images for 22 January 2005 |
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Still more work on Yana's laptop today. For some reason I'm running into particularly many problems. For example, using POP3 over an ssh tunnel works fine when I'm logged in as myself, but when Yana tries it, the remote popper process hangs in sbwait.
Spent some time working on my sprinkler project, and got the power supply working. It's surprising how much time it can take when you're out of practice. The result was also pretty ugly; I think I should consider making my own PCB boards just to make them look better.
At least the power supply worked. Connecting it to the existing relays confirmed a vague suspicion I had had: to control the water pump (700 W), Barry “too much is barely enough” Engel had installed a three-phase power relay that probably handles 10 kW. The coil also draws 1.35 A at 24V (yes, 34 W, 5% of the rating of the pump, just to keep the contacts closed):
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More to the point, of course, is that the old sprinkler controller was only rated for a total of 0.7 A for everything. So it's no wonder that it died. Thanks, Barry.
| Sunday, 23 January 2005 | Echunga | Images for 23 January 2005 |
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What a day! I had intended to continue with my sprinkler control, but there was so much else to do that I didn't get round to it. In the morning started brewing a single batch of Weißbier in the hope that it might be less stressful than two at a time. A number of things stopped this from being the case;
Installing software is still too complicated, though. After we got the Microsoft partition working, I still had a lot of trouble getting mail to work. And I should know this stuff backwards.
Despite my expression of disdain, Michael also sent me an invitation to join gmail, Google's web mail service. I did sign up and got it to work, but I was left with the singularly powerful feeling “so what?”. What I found was:
Add to that the fact that you need network access to read the mail at all, and even then it's not as fast as a local system, and I'm still baffled as to why anybody would bother.
| Monday, 24 January 2005 | Echunga | |
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The last day before Yana leaves for Europe, and I still didn't have mail working properly on her machine. Mail is a real problem: SMTP isn't designed for moving mail spools from one location to another at the wish of the destination, and POP software is buggy, slow and insecure. My first attempt was to run fetchmail and postfix over an ssh tunnel. For reasons that I wasn't able to fathom, it ran into authentication problems that didn't occur when making a direct connection. In addition, fetchmail appears to deliver to the local MTA, postfix in this case. Playing with the postfix transport maps made me very concerned that a change in the domain name could result in postfix sending the newly arrived mail back again, where it would be rejected due to a transport loop.
In the end gave up with POP and made a slight modification to the manual method I have used to get my mail in the past. It basically compresses the mail spool and transfers it with scp, making it an order of magnitude faster than fetchmail. It also leaves behind backups on the source system in case of problems. The whole thing took me about 10 minutes, much less than the frustration of trying to get fetchmail working.
| Tuesday, 25 January 2005 | Echunga | Images for 25 January 2005 |
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Yana finally left this morning in the middle of the night. She'll be spending the night in Tokyo and arriving in Frankfurt tomorrow evening local time. Went into her bedroom and discovered that she had taken rather a superficial view of her obligation to leave the place tidy:
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Fortunately, the cleaners came today, so Yana was able to spend some of her money doing what she should have done herself.
Work was interrupted by a discussion on Makefile structure. Sometimes you can spend more time talking about these things than fixing the problem, so I chose the latter.
In the evening finally connected up my sprinkler controller:
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The most difficult part was the wiring: the software worked out of the box. Also had heat problems with the power supply: it's surprising how little heat these small heat sinks can dissipate. The power supply delivers about 35 V unfiltered from the 24 VAC power supply, and the sprinkler solenoids draw about 0.35 A at 24 V. That means that the voltage regulator must dissipate 11 × 0.35 = 3.85 W. That's enough for the heat sink to be too hot to touch. Similar considerations apply for the 12 V supply. It looks as if I'll have to rebuild the power supply with bigger heat sinks. The regulators can handle 1 A each, so that's not the issue.
| Wednesday, 26 January 2005 | Australia Day | |
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Quiet day today. Chris Yeardley had arrived last night, but she wasn't staying long, and it was too hot to go riding anyway. She brought some old computers with her, though: a 386 and 486, each with 8 MB memory. They may come in handy for things like the sprinkler project. Started thinking about installing an old version of FreeBSD on them, but didn't get very far. The 386 didn't have a CD-ROM drive, and the 486 appears to have problems with the disk drive, though that could be a BIOS problem.
She also brought a Dell Inspiron 8100 with intermittent disk problems. There wasn't much to be seen, but it sounds like another contact problem. Spent yet another fruitless effort searching the impossible Dell web site for documentation. This time even Google didn't help much, though Dell's habit of giving the manuals slightly different titles each time didn't help much. Found an online version online version on their Japanese support site, but who knows how long it'll stay there. There's nothing obvious on the site to suggest that the information might be there.
Didn't do much else. Hopefully I can find more time to not do much.
| Thursday, 27 January 2005 | Echunga | Images for 27 January 2005 |
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Decided to order some components online from Jaycar, the Australian electronics component retailers. They have quite a reasonable catalogue, but it's nearly a year old, and anyway, what's the web for?
Good question. Jaycar's web site is no more obnoxious than others, but it looks really bad compared with a good catalogue. It's nice to be able to find things by keyword, but you need to enter the keywords one at a time. Looking for a housing for the power supply for the sprinkler, I entered housing and got things related to security cameras, only. The entries for the individual items are not as well formatted as in the catalogue, and they display at only 10 items per screen, making navigation difficult on the one hand, and requiring clicks on the more >> button on the other hand to be able to see enough detail. On the positive side, many have links to documentation; the catalogue doesn't have anything similar.
The real problem was placing the order, though: I started entering stuff and then was distracted by something else. Came back and my order had expired. That's common enough, but what a pain! You'd be really upset if you wrote something down on paper, came back an hour later and discovered that the ink had faded away. The real problem here is the issue of sessions: at a time when most computers didn't have much power, it seemed sensible to get the server to do most of the work. It doesn't any more, but communication between software on the client and on the server is far too complicated. It needs a complete rethink.
On the work side, got my O_DIRECT kludges sorted out, and discovered it was using inordinate amounts of memory. While testing that, discovered that the newest version of the project doesn't work at all on my system: it SIGSEGVs immediately. Strangely, nobody else had seen that.
| Friday, 28 January 2005 | Echunga | Images for 28 January 2005 |
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Ken Simmons and his mate Phil showed up today to install the range hoods that we bought in Singapore last year:
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Shane Adcock, the electrician, put in a brief experience and had interesting information: he's building a new office not too far from here and installing networking. He asked a number of questions, but also came up with some interesting information: Cat 6 cable requires different tools from Cat 5E, and they don't seem to be available.
More importantly, though, is that the Echunga telephone exchange will be equipped with an ADSL DSLAM in the next few weeks. Checked out the impossible Telstra web site (what suburb? Echunga has a population of 500) and found nothing (“Congratulations! BigPond Broadband Satellite is available”). Why do so many companies have such completely useless web sites, and why do almost none of them make it easy to find contact addresses and phone numbers? Found a phone number anyway, called them up and got somebody who was more interested in transferring my phone lines back to Telstra, but finally determined (after I insisted) that ADSL was indeed coming to Echunga. No further information, but she did put me on a list, though it's not clear what the purpose of the list is.
| Saturday, 29 January 2005 | Echunga | Images for 29 January 2005 |
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Things are really slowing down! Didn't do at all much today, and enjoyed every minute of it. A bit of—very necessary—tidying up, and that was about all.
| Sunday, 30 January 2005 | Echunga | Images for 30 January 2005 |
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And another quiet day. Up late, to bed early. The weather was ideal for riding, but didn't do that either: it seems that Yvonne was also feeling as lethargic. It's funny how you feel tired when the pressure lets up.
Despite that, did do a little “work” work; we have a deadline looming, and as a result of the bugs of the last couple of days, I was a little behind. Got things working and discovered in the process that there were still some persistent bugs present. Got that sorted out, but the test results weren't ready by evening.
| Monday, 31 January 2005 | Echunga | |
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Finished work on the latest stage of my O_DIRECT kludge today. The result was a 10% decrease in performance, but notably a 90% increase in page reclaims. I suspect that this might be related to mallocing large quantities of memory, and wonder whether malloc frees the address space when it frees memory. In any case, no cheap gains there.
A couple of weeks ago I bought a second-hand Apple laptop from Hugh Blemings, and it arrived today. It's a PowerBook G3 SCSI, which is apparently also known as WallStreet—maybe. This machine has a 400 MHz processor and an 18 GB disk, both of which are only available on the “bronze keyboard” and “FireWire” versions, but this is neither of those.
Initial experiences were interesting: on the one hand it's full of eye candy, and it's anything but intuitive to use. On the other hand, it's the first laptop I've ever been able to use out of the box, sort of: the BSD interface makes up for a lot of other pain. It remains to be seen whether I can get it to behave the way I want.
Into town in the afternoon for a meeting. Looks like we have some new things under way, including a beer bust on Fridays—shades of Tandem—and other things that will require me in town more frequently. We're living in interesting times.
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