How can I stop LTSPice from using the hard drive

[Joerg]

Hello Folks,

Title says it all. LTSpice constantly grinds on the hard drive, storing
raw data and what not. In my case it's all on a LAN drive so this is
especially annoying. Plus that will wear it out over time, not good at
all. With a 2GB RAM machine there is no reason whatsoever to store 20M
of raw data on every single run.

How can I stop this?

 

[Kevin Aylward]

Hello Folks,

Title says it all. LTSpice constantly grinds on the hard drive,
storing raw data and what not. In my case it's all on a LAN drive so
this is especially annoying. Plus that will wear it out over time,
not good at all. With a 2GB RAM machine there is no reason whatsoever
to store 20M of raw data on every single run.

How can I stop this?

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
www.anasoft.co.uk

 

[Rich Grise]

Hello Folks,

Title says it all. LTSpice constantly grinds on the hard drive, storing
raw data and what not. In my case it's all on a LAN drive so this is
especially annoying. Plus that will wear it out over time, not good at
all. With a 2GB RAM machine there is no reason whatsoever to store 20M of
raw data on every single run.

How can I stop this?

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

 

[Frank Buss]

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

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:

http://support.microsoft.com/?scid=kb;en-us;257405&x=10&y=8

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.

 

[Joerg]

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:

http://support.microsoft.com/?scid=kb;en-us;257405&x=10&y=8

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.

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 ...

 

[Joerg]

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.

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.

 

[Helmut Sennewald]

Hello Folks,

Title says it all. LTSpice constantly grinds on the hard drive, storing
raw data and what not. In my case it's all on a LAN drive so this is
especially annoying. Plus that will wear it out over time, not good at
all. With a 2GB RAM machine there is no reason whatsoever to store 20M of
raw data on every single run.

How can I stop this?

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.
http://www.mydigitallife.info/2007/05/27/free-ramdisk-for-windows-vista-xp-2000-and-2003-server/Best regards,Helmut

 

[Joerg]

Hello Joerg,

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

Yeah, unfortunately. I wish they didn't.

Running any SPICE over LAN is wasting time.

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 :-(

Using a RAM-disk may be an option, but I don't understand
why you think your harddsik will not stand LTspice.

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.

Hendrik posted this link in the LTspice Yahoo group when he praised this
RAM-disk.
http://www.mydigitallife.info/2007/05/27/free-ramdisk-for-windows-vista-xp-2000-and-2003-server/Best 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.

 

[Helmut Sennewald]

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.



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.

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


---
# 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

 

[[email protected]]

Hello Folks,

Title says it all. LTSpice constantly grinds on the hard drive, storing
raw data and what not. In my case it's all on a LAN drive so this is
especially annoying. Plus that will wear it out over time, not good at
all. With a 2GB RAM machine there is no reason whatsoever to store 20M
of raw data on every single run.

How can I stop this?

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

 

[Joerg]

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.

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 ...
<gasp> ... the bin with the 4046 was empty. Just like our stash of elk
sausage, we just ate the very last one :-(

 

[Helmut Sennewald]

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 ...
<gasp> ... the bin with the 4046 was empty. Just like our stash of elk
sausage, we just ate the very last one :-(

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

 

[Joerg]

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.

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.

 

[Helmut Sennewald]

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.

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

 

[Joerg]

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.

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.

 

[Joerg]

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

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.

 

[Joerg]

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.

It was pointed to the local hard disk. But it still writes the *.raw
files to wherever the sim files are. So now I ferried those to the local
HD, violating a ground rule here. In the evening I must ferry all this
back. T'is the rule, to make sure client files are clearly separated.

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.

It's Linux and it does cache. Not much to set there, it's a Western
digital box with only a miniscule amount of control valves. Basically
you can set some permissions, that's pretty much it.

This is a common problem on LAN servers when using LAN hostile
applications. Writing temporary data to a temp file is so 1980's.

That's why I was hoping LTSpice was post 1980

It could store an image in RAM and then do all the fast stuff from
there. But no ...

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.

It's a regular Ethernet (wired) LAN. SMC Barricade router, Western
Digital MyBook World with a LAN port, right next to that router.

 

[Helmut Sennewald]

Hello Folks,

Title says it all. LTSpice constantly grinds on the hard drive, storing
raw data and what not. In my case it's all on a LAN drive so this is
especially annoying. Plus that will wear it out over time, not good at
all. With a 2GB RAM machine there is no reason whatsoever to store 20M of
raw data on every single run.

How can I stop this?

Hello Joerg,
I just run a simulation with LTspice generating a 100MB raw-file.
The simulatiomn tooks 90sec and I saw the hard disk lamp blinking about 140
times.
That's by far not any stress for a harddisk.

LTspice uses internal caches to keep the waveform data.
You can look traces in a 100MByte raw-file with terriffic speed.
That's only possible because LTspice keeps most data in RAM too
as long as you don't run out of RAM.

Best regards,
Helmut

 

[Joerg]

Ok, bad guess and bad design. Temp files should stay local.


I have a working directory on 4 of my local machines (2 of which are
laptops). The local documents, client, and working projects are setup
to replicate to the file server, data dumpster, and backup device. I
use Windoze Briefcase for the Windows boxes and rdist for the Linux
stuff. All are automatic or cron based. The trick is that I never
edit the files directly on the file server. Edits are always done
locally. Synchronization is always one way, from the local machine,
to the file server, never the other direction. Of course, I'm very
careful to maintain accurate date and time information. While there
was a major learning exercise many years ago, it hasn't failed for
maybe 8 years.


Any particular model number WD NAS box? I think you'll find that your
WD box does NOT cache writes. I need he model number to be sure. Last
time I ran IOZONE on some NAS boxes, it was apparent that there was
plenty of read cache, but writes went straight to the drive. Look on:
<http://www.smallnetbuilder.com/content/view/85/93/>
for NAS benchmarks and tests on your WD. If you feel ambitious,
compare the results with a "real" server, which uses main memory for
caching both reads and writes. I've replaced several NAS boxes with
Linux servers that simply couldn't keep up with the load (mostly brain
dead applications that scribble all over the server, open huge number
of files, do numerous sync operations for no obvious reason, etc.


Dunno. I was doing SPICE in college in the last 1960's.

My guess is that someone didn't test the hell out of every possible
network configuration or goofed by forcing a temp file to live across
the network.


It could, but how old Switcher CAD (LT Spice)? Probably as old as
Linear Tech which was founded in 1981. As I recall, the IBM PC
arrived in the same year.


Ummm.... Model numbers? Network speeds? Media (CAT5, coax, fiber,
two tin cans and a string)? Gigabit? Number and type of network
boxes located between the WD NAS box and your workstation?

It's the Western Digital WD5000G031. CAT-5 wiring in home run method,
all goes to the SMC. A wireless hangs on it as well but only gets turned
on when needed. Not Gigabit, 100Mbit/sec. It is plenty fast for me and
none of the other programs uses the data directory to store temp stuff.
Make no sense anyhow.

Well, at least you supplied the WD model number.
Is it My Book World I or World II? (just curious).
<http://www.wdc.com/en/products/Products.asp?DriveID=340>
It does gigabit. Are you using gigabit?

Nope.


Review of My Book World:
<http://www.smallnetbuilder.com/content/view/30140/75/1/3/>
Basically, the reviewer says the performance sucks:
<http://www.smallnetbuilder.com/component/option,com_nas/Itemid,190>
Looks like near the bottom of the list for 100mbit/sec write
performance. 2nd from worst at gigabit speeds:
<http://www.smallnetbuilder.com/component/option,com_nas/Itemid,190/chart,12/>

Yes, it is slow. I knew that before I bought it but that is of no
concern to me because all it does is store data from office and CAD
applications. Not much bandwidth needed there. I just wanted something
from a reputable manufacturer without the big blue pricing.

I have a suggestion. Setup one of your Linux machines to play server
for a while. Nothing fancy, just an NFS or NETBIOS shared directory.
Drop one of your client directories onto the Linux server, and see if
the disk bashing and performance problems go away. If you have time,
run some iozone benchmarks, but a live test with the problematic
application is probably good enough.

Well, I don't have a Linux machine. But it's ok, when there is some time
(and no honey-do projects ...) I'll do the RAM disk, should fix it.

 

[Joerg]

You say you have a lot of RAM, >=2G ? Have you considered a flash drive
that plugs into a USB port, or an SD or CF card if your PC will accept it.

USB flash drives are freaking slow :-(

This PC unfortunately does not accept SD cards.