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#71
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In article et,
UltraJohn wrote: Pete Schaefer wrote: He could also go with the Athena card instead. That does have VGA on it. And it's a faster processor. "Evan Carew" wrote in message ... Well, it doesn't come with a video card if that is what you meant, however, that is a relatively simple matter to fix. PC104 video cards are quite reasonably priced & even support 1/2 or 1/4 VGA standards. Looking closer at it the biggest shortcoming I see now is the lack of ram the card only handles 32mb and Linux is very memory intensive and running With some care in kernel tuning, you can get the memory footprint *way* down. The _real_ memory pig is the X server. With a text-only display, it is *amazing* how much you can do in 'small' memory configurations. 8 megs is _plenty_ for running a dedicated 'firewall' box, for example, and a _386DX/33_ will handle a full T-1, in that application, with cycles to spare. |
#72
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I ended up ordering a Via TC motherboard as it will take up less space
than the CL with cumbersome DC converter and hopefully reduce RFI, and if there is still RFI I have only one variable to contend with vs two. I did not go with the PC104 format although I did look at this at length. I already have considerable experience with the VIA now, a case and airplane bay designed for it (17cm x 17cm) and a very lean kernel tweaked for it. Also the VIA is a tad more mainstream with this typically resulting in better doc and support for drivers. Also I can boot off a write protected USB flash card (USB flash memory as IDE did not work for me, too much data corruption in unexpected power off scenarios). I don't know which PC104 have this ability. Anyone with PC104 experience would probably argue with this, but I have had my fair share in the past of getting odd behavior with a video, sound, ethernet driver and having to slowly track it down. I know all the MB sensors on the VIA are queryable in linux (ie CPU temp, all the voltages, etc..) For me, memory is very important and 512Mb a mininum. Why so big when my entire custom Linux distribution with X and Java fits on a 128Mb USB flash card? As a Robert pointed out the kernel is a small memory consumer, X is the real hog. And with potentialy complicated displays this would grow even further. Most importantly this distribution runs in entirely in memory, there are no writes by the OS to the main USB flash card which is write protected. As such there is no swap space, and hence any malloc calls need to actually find real memory not virtual memory. Flash memory degrades with each write, areas such as swap and log directories can receive an enormous # of writes with often little effort. Some benchmarks have shown corruption after only 10,000 writes. Having a memory block go bad (which is just a matter of time given the nature of Flash) can lead to odd/unpredictable behavior (the worse kind), something I want to entirely avoid. The secondary USB flash card, which is not write protected, holds the log files and mp3 files. 'Non critical' files. I also wrote the data logging program to only flush the OS writes every X seconds, not on each log write. I could add an OS swap file to this partition but I still could end up with corrupted swap space and the additional writes would also shorten the life of the USB flash card. Additional memory is cheap insurance (in additional $40) in avoiding these problems and has an added benefit of performance. If I was going to start from scratch I might go with the PC104 platform but neither platform seems to be vastly superior to the other. And the Devil you know... |
#73
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jcpearce wrote:
I ended up ordering a Via TC motherboard as it will take up less space than the CL with cumbersome DC converter and hopefully reduce RFI, and if there is still RFI I have only one variable to contend with vs two. Nice write up of what your thinking is. As you said probably either system could work but your more familiar with this avenue. This has been a very positive thread with no would getting there"panties up there crack" g. I'd be interested in any updates your might have, I have already bookmarked your web site and will check in from time to time. I wanted to check on the cost of the Athena system unfortunately they require you to log in and register for a quote, I wasn't that interestedvbg. Good Luck John |
#74
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I think the Athena goes for around $600.
"UltraJohn" wrote in message ink.net... I wanted to check on the cost of the Athena system unfortunately they require you to log in and register for a quote, I wasn't that interestedvbg. |
#75
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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 JC, For what its worth, the previously described PC104 486 based system was used by my company to controll a filter system & write to an X display at the same time running Linux. That system only had 128MB of RAM & that might have been too much. All applications ran from RAM. The problem with X apps that run on Linux is that when they are developed with a toolkit such as Motif or GNOME, you end up including quite a lot of baggage along with the X app. One way to solve this is to search for a "light" toolkit or to simply write your app in plain X yourself. People often say of Such apps "Hey your X app really starts fast!" That being said, you should not be surprised when X sucks 50% of the performance of your CPU up on such a box. On my production unit, the X Application was the only one running & didn't need a desktop. Under the hood, my drivers supplied the needed data to the X app. Hopefully, it goes without saying that the kernel was a custom striped down version with my drivers & very little else. Evan -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFCGmkWpxCQXwV2bJARAgFMAKC9u8jXMDfDqNQ60wh+rx flGNn/XgCfQNeV 0QqkahRlAra3uhd6QPNS5xw= =xcmq -----END PGP SIGNATURE----- |
#76
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Evan Carew wrote:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 JC, For what its worth, the previously described PC104 486 based system was used by my company to controll a filter system & write to an X display at the same time running Linux. That system only had 128MB of RAM & that might have been too much. All applications ran from RAM. Good points Evan. A lot can be done if you set up a custom system. Up until I switch to an AMD 64 bit system I ran slackware in which you can select indiviual packages to install. You could get a very small system if you wanted. Stick to on editor one window system and a custom kernel and you can get a rather complete system pretty small. Take a look at most 'Boxed' systems under /bin /sbin /usr/bin and /usr/sbin and you will see a lot of programs that you will never use! John |
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