How can I stop LTSPice from using the hard drive

well. I remember years ago being able to setup a ram dive on, I belive, an atari. No doubt something like this will exist for windows. i.e the program thinks it writting to say k:\\ drive, but it aint. I suggest a web search

Kevin Aylward

Are you allowed to download the file to your local box, work on it, and then upload it? That would get rid of the LAN bottleneck; otherwise, there's the ramdisk, but if you have enough ram, it shouldn't need to swap out any data, because the program should exploit it.

Good Luck! Rich

For DOS there was a similar program included. For Linux a ramdisk is included, too (if the kernel was compiled with support for it). For Windows XP there is no built-in program available. But looks like Microsoft has a free program for Windows 2000, which should work for Windows XP, too:

Maybe this helps Joerg. I assume it saves the files to the temporary folder, which can be specified in LTspice with Tools->Control Panel->Operation->Directory for Temporary Files.

--
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Yes, a RAM disk is an option but I was hoping that I wouldn't have to do that anymore in this day and age. Maybe I have to ...

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Regards, Joerg

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I've got tons of RAM but LTSpice is one of the few programs that still grinds on the HD incessantly. Local box is an option but it makes a mess because I have the files assorted on the LAN drive by clients. That way I don't have to copy back and forth.

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Regards, Joerg

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"Joerg" schrieb im Newsbeitrag news:jESAk.1055$ snipped-for-privacy@nlpi068.nbdc.sbc.com...

Hello Joerg,

Every SPICE program stores the data on the harddisk or whereever you will have the output file(.raw).

Running any SPICE over LAN is wasting time. Using a RAM-disk may be an option, but I don't understand why you think your harddsik will not stand LTspice.

Hendrik posted this link in the LTspice Yahoo group when he praised this RAM-disk.

regards,Helmut

Yeah, unfortunately. I wish they didn't.

Seems like I have to copy the files from the LAN drive to the computer, runs the sims, then copy everything back to the LAN server :-(

Well, it keeps going costantly. It's head is moving about all the time. It'll stand it but that reduces overall lifetime. What's really sad is that there really isn't any good rerason for it.

regards,Helmut

I seems like the old RAM disk concept needs to come back out of the basement. I thought this phase would be over these days, but ...

Anyhow, thanks for the hint. Since you are a LTSPice guru now I know there really isn't any secret setup I could fiddle with. Got to do the RAM disk.

--
Regards, Joerg

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Hello Joerg,

I followed the messages of the link above and it seems there is a later version. It looks like it's for XP and Vista.

Best regards, Helmut

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#  Gokhan
June 26th, 2008 17:45
47

OK, here is the latest file and how to install;

1. download the updated version at this link;
http://vista.inoxa.de/Dateien/Gavotte_RAMdisk__v.1.0.4096.4_25.01.2008.zip
The version posted here might also work, but anyway. Extract the archive to 
a directory.
2. Go to the Control Panel and click Add Hardware
3. Click Next and wait for the search to complete.
4. Choose "Yes, I have already connected the hardware" and click Next
5. Scroll to the very bottom and highlight "Add a new hardware device" and 
click Next
6. Choose "Install the hardware that I manually select from a list" and 
click Next
7. Wait for the search to complete and click Next
8. Highlight "Show All Devices" and click Next (warning: this part may take 
a few minutes)
9. Click Have Disk. (Important! Be sure not to click on anything else or 
scroll through the lists before you click Have Disk. Doing so will screw up 
this process.)
10. Click Browse and locate the folder you saved the rramdisk.inf file in, 
select ramdisk.inf and click Open
11. Click OK, then Next and Next again.
12. Click Continue Anyway if a warning pops up and then Finish
13. Right click on the "ram4g.reg" file in the extracted directory and 
"merge".
14. Now when you launch the ramdisk.exe utility, you should be able to see 
the options properly enabled. Set the desired ramdisk size and click OK. It 
should be ready to use at the default drive R:

Good luck!
# Gokhan

If you want, point the LAN drive letter to a local location with the DOS SUBST command.

Thanks, Helmut. The firewall blocks this one for some reason but I'll get it somehow.

BTW, I just tried your 4046 PLL file from the Yahoo board (CD4046_h_test.asc) and receive an error "Singular matrix: Check node n002 Iteration No.1". Tried a 10M to GND, then across the timing cap, doesn't work. Is there anything simple I might not have done right? Node n002 is the C1B connection.

Wanted to go into the lab instead and fire it up on the bench and ... ... the bin with the 4046 was empty. Just like our stash of elk sausage, we just ate the very last one :-(

--
Regards, Joerg

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Hello Joerg,

I just downloaded all files from the Yahoo folder Lib > CD4046 and run the simulation with "CD4046_h_test.asc". It worked out of the box.

Please reset your SPICE settings in the Control Panel. It can be accessed by clicking on the "hammer" icon.

Control Panel -> SPICE "Reset to Default Values"

I have used LTspice version 2.25b.

Best regards, Helmut

I've got version 2.24i. It was at the defaults so when I clicked it nothing changed.

And yes, your files does work when you don't connect anything. But the

4046 needs at least R1 and C1 (the loop you already have in there). When you connect a capacitor to C1 the error message pops up.

--
Regards, Joerg

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Hello Joerg,

The pins C1a, C1b, R1 and R2 are not used internally in this SPICE model. Instead the model contains a behavioral oscillator set by this line:

VCC1=5 FMIN=0.1e6 FMAX=0.3e6 SPEED=1.0 TDEL1=20n TRIPDT1=8n

Best regards, Helmut

Ah! I think I've got it. Your's is probably a top level model where the min max frequencies etc. can only be entered via directive. Looks like Andreas Czechanowsky's model might work for the VCO part.

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Regards, Joerg

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Yep, pretty much the millisecond you must have answered this dawned on me when I saw that Spice directive in your file. I'll see if Andreas' modle works for the VCO.

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Regards, Joerg

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Setup RamDrive and point LTSpice to it.

Well, there is no swapping; LTSpice puts results to a file every time results are calculated - and that is where the complaint comes in.

Others have covered the RAM disk issue adequately. I'll deal with optimizing what you have.

I fired up LTSpice 2.25b, and noticed that: Tools -> Control Panel -> Operation has a setting for the location for "Temporary Files". I haven't tried it with your configuration, but methinks it will help considerably if you point the temp file directory to your local hard disk, and not to the server.

You apparently also have the LAN drive set to NOT cache writes. That results in an immediate write to disk on your server. If you're using the desktop versions of Windoze as a server, control over write caching is under the properties for the disk drive. If you're using a real server operating system (i.e. W2K server, Server 2003, Linux server), there's some fine tuning available, such as how long to wait before flushing RAM to the hard disk.

This is a common problem on LAN servers when using LAN hostile applications. Writing temporary data to a temp file is so 1980's. With the availability of cheap RAM, such applications should use virtual memory instead. I have to deal with other business apps that also do it wrong. The solution is lots of battery backed up RAM in the server and lots of speed in the LAN. Nothing less than gigabit ethernet will suffice these days. Multiple ethernet cards in the server are a plus so that backups and the bosses streaming video don't bog down the LAN. However, none of this added RAM or LAN speed is going to do you any good if your server immediately scribbled everything to the drive. You need a write buffer cache.

Anyway, tell me what you have for a server and LAN, and I'll suggest tricks to optimize (or upgrade) what you're using.

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This reflects the fact that Windows uses a *huge* disk cache by default (hundreds of megabytes if no other program requests the memory!), and the folks at Microsoft seemed to equate using a RAM disk to "I want really fast performance" (as opposed to Joerg's "I don't want my mechanical hard drive grinding"), which a huge cache provides, so this is why they make you go to some effort to get a "real" RAM disk.

Or at least that's my interpretation of events. :-)