Question for Database EXPERTS about implementing an Embedded Database

One of my current projects is to implement a Embedded pure java database with a smaill subset of SQL. Since I estimate it will take me at least 400 man hours (based on my intial unfinished attempt) to build something robust and usable, I thought I'd ask my fellow java folks for suggestions. The SQL and parsing is no problem, but the best way to implement the records structure is. My first approach would be to represent each table in a seperate file (file defined as a standard OS file). Each record would have a fixed byte length, say 256.
A seperate definition file would containt the column names, type, and maximum byte length for the column. So the data file would be a repetitive list of 256 byte rows, some arbitrary byte value could be used as a 'filler' for the part of a row not being used. When a row is deleted, the entire row is merely overwritten with the filler. The next inserted record would then take its place.
String types, numeric types, and small strings would be written directly to the data file at their appropriate byte offset from the start of its respective byte row position.
Complex or large data types like multimedia and memos would merely have a filename string pointing to another file. Things like security and encryption (hopefully) could be added on later. My main concerns are about how to implement an efficient indexing algorithm, and how to minimize the space required for each table, while maintaining simplicity.
Furthermore I currently plan to use the most basic and common classes to implement this (Java I/O API, and of course some of the SQL API to implement JDBC). Any advice on other APIs that may benefit this? Any red flags come up yet?

One of my current projects is to implement a Embedded
pure java database with a smaill subset of SQL. [ ... ]
fellow java folks for suggestions. The SQL and parsing
is no problem, but the best way to implement the
records structure is.I once (1981) did it this way: a database file consists of consecutive pages, all of equal size; say, 4KB per page. Every page consists of consecutive cells; every cell can store a short, so 2K cells can be stored in a page.
Cells in a page serve two purposes. From the bottom to the top, the cells represent offsets in the page where the records are stored and from the top to the bottom the cells are used for the actual data. The first cell of the page contains the offset to the first free cell in the page; the second cell contains the offset to the first occupied (data) cell in the page. Any record offset cell containing zero (0) is a free record offset cell.
This scenario implies that the maximum record length is 4KB - 4*3 bytes.
A record takes up one offset cell, as many cells that are needed for the acual data, preceeded by a cell containing the length of the record. The offset cell contains the cell number where the record starts (the length cell).
Records are addressed by their page number and by their cell offset number [PR]. The R number points to the cell containing the actual offset of the record. The [PR] number doesn't change during the lifetime of the record. (this is important).
Inserting a record is easy: find a page with enough room and store the record in that page. If no page is available, add another page to the database file. Deleting a record is simple too: delete the record, zero out the offset cell and compact the data part of the page. Updating a record is a bit more complicated. If the record size shrinks, stuff is easy. If the record size grows, and it doesn't fit in that page anymore, another page has to be found. The old data is removed and a small 'indirection record' is inserted instead. This new record contains the actual [PR] number where the new (larger) record is stored. The original R cell has a few more bits available. 2K different numbers take up 11 bits. The cell itself can store 16 bits, so one bit can be used, indicating that it's not pointing to an actual data record, but its offset is pointing to an 'indirection' record instead. Some careful fiddling takes care that subsequente updates of a record keep this indirection stuff limited to just one indirection (this is true, believe me).
Pages are loaded in core, and swapped out whenever necessary. Every loaded page has a page number and a 'dirty bit' attached to it. Whenever this bit is set, the page has to be written back to disk if it needs to be flushed from memory (due to memory exhaustion etc.) otherwise, the memory can simply be released. A simple LRU (Least Recently Used) list does wonders here.
B-tree records can be stored as ordinary records too; this implies that the indexes of the tables (a bunch of records) are ordinary records too. Note that these spare 5 bits (one taken indicating an 'indirect' record) can do wonders here. As a matter of fact, a bit indicating that its cell is pointing to a B-tree node came in very handy. And still three bits free for other miracles! ;-)
I better quit before I turn another message into a novel again.
kind regards,
Jos

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hi there online experts,
i have an hp dv1432us. fab little machine. works great.
lately the fan was running a lot (almost constant) so i vacuumed the fan inlet and blew air in the outlet. fan now cycles on and off every minute or 2. everest sensor software says CPU is at 52-59 degrees celsius.
questions:
1) is it normal for the fan to cycle on and off every minute? in other words, what is a the normal amount of fan running for this machine?
2) what is the normal temp range for this CPU (and hard drive, while we're talking baout such things)
given that info, is it time for a major cleanout of this thing? will the possible heat buildup cause damage if i do nothing?
3) if i am ever so careful, should i take this apart and clean it? it's been 5 years of a lot of hours of use.
4) can i disassemble it down to the heatsink without major risk of ESD damage? I have home-built many case PC's, so i am not a newbie . . . how risky is it to take this thing apart and clean that heatsink?
eagerly looking forward to any and all info, best, justin

justinlockehp,
A couple of good documents on hp.com address this issue:
Fan Runs Constantly, the PC Operates Slower than Expected and Generates Heat
Reducing Heat and Fan Noise by Cleaning Air Vents
1) This can be normal depending on the amount of work the notebook is doing, the amount of heat being generated, and the fan control algorithm in the BIOS.
2) I don't have the specific range for the PC or components but I can tell you that todays notebooks are much warmer than they used to be. The GPUs and CPUs generate much more heat than ever before.
3) Use the instructions in the document above, anything further would probably be more work than required. However, the instructions are here: http://h10032.www1.hp.com/ctg/Manual/c00636251.pdf.
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-wes
I am an HP employee.

Please read my question carefully, this is, I think, a question for the experts. It's not the usual name change question. When I setup my new MacBook Pro, something slipped by me and my computer was named First-Lasts-MacBook-Pro (using my real first and

Please read my question carefully, this is, I think, a question for the experts. It's not the usual name change question.
When I setup my new MacBook Pro, something slipped by me and my computer was named First-Lasts-MacBook-Pro (using my real first and last name).
I changed the computer name in Preferences/Sharing to a new name and Preferences/Accounts to just be Mike. I can right click on my account name, choose advanced, and see that everything looks right.
However, If I do a scan of my network with my iPhone using the free version of IP Scanner, it lists my computer as First-Lasts-MacBook-Pro! And it lists the user as First-Last.
So even though another Mac just sees my new computer name, and my home folder is Mike, somewhere in the system the original setup with my full name is still stored. And it's available on a network scan. So my full name might show up at a coffee shop.
Can I fully change the name without doing a complete re-install of Lion and all my apps?

One thought... you said the iPhone displayed your computer's old name? I think that you must have used the iPhone with this computer before you changed the name. So no one else's iPhone should display your full name unless that iPhone had previously connected to your Mac. For example, I did this exact same change, and I use the Keynote Remote app to connect with my MacBook Pro. It would no longer link with my MacBook Pro under the old name, and I found that I had to unlink and then create a new link under the new name. So the answer to your question is, there is nothing you need to do on the Mac, but rather the phone, and no other phone will display your full name.

Are these things possible in PDF forms? Questions for the experts

Hi,
I have a project where I need to create an online application system, where the user has to fill in a form where the results have to be saved into a database.
I wanted to create a html based form, but then someone told me PDF can also do cool things, so I’m researching that road.
I already managed to create a simple form and submitting it to a web service (java servlet in my case) and that works pretty nicely.
I'm new to the whole PDF form creating and I’m wondering if certain things are possible. So I’m trying the experts in this form for a yes/no answer.
Are the following things possible with PDF forms:
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4) After I submit the form, is it possible to lock the form so that no other changes can be made? In other words, you may only submit once.
5) Possible to activate the print button after the form has been submitted?
6) Can a drop-down lists be dynamic? Instead of hard coding the list, calling a web service to fill the values?
Thanks in advance for any insight,
Kind regards
Ido

Hi Paul,
thanks for the quick answer. No my next challange is how to do things
1) validation: number & date checks, eg, a number should be higher than 4, or be a valid number/date
<answer> Yes
I think this is done through the object properties
2) If I answer A at question 1, I should skip Question 2 and go directly to Question 3. Is it possible to hide Question 2, depending on what I answered at Question 1?
<answer> Yes
This is done with subforms and scripting?
3) Is it possible to attach files to the form, like a photo? And also upload it to the web service.
<answer> PDF does support the ability to have attachments. They would be includeed as part of the PDF so you woudl have to submit the entire PDF and then extract the attachments when you get the file to the server. Note that you will require to Reader Extend the document to allow a Reader user to add the attachment. This is not a requirement if you are using Acrobat.
Have to look into this one.
4) After I submit the form, is it possible to lock the form so that no other changes can be made? In other words, you may only submit once.
<answer> Yes
Also through scripting?
5) Possible to activate the print button after the form has been submitted?
<answer> If you add a print button on the form then the answer is Yes. The application that houses the PDF will jhave print capabilities and that one is much more difficult to hide. You can set it up so that the form cannot be printed then return back the locked version with printing enabled but a round trip to the server is required for that.
Print button will be fine by now, probably also done by scripting
6) Can a drop-down lists be dynamic? Instead of hard coding the list, calling a web service to fill the values?
<answer> Yes but the form will require LiveCycle Reader Extensions if you are using Reader. Reader Extensions is not required if you are Acrobat.
Ahh, perhaps fixed list will be ok for version 1

Design question for database connection in multithreaded socket-server

Dear community,
I am programming a multithreaded socket server. The server creates a new thread for each connection.
The threads and several objects witch are instanced by each thread have to access database-connectivity. Therefore I implemented factory class which administer database connection in a pool. At this point I have a design question.
How should I access the connections from the threads? There are two options:
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b) Should I develop a static method in my factory class so that each thread could get a database connection by calling the static method of the factory?
Thank you very much for your answer!
Kind regards,
Dak
Message was edited by:
dakger

So your suggestion is to use a static method from a
central class. But those static-methods are not realy
object oriented, are they?There's only one static method, and that's getInstance
If I use singleton pattern, I only create one
instance of the database pooling class in order to
cionfigure it (driver, access data to database and so
on). The threads use than a static method of this
class to get database connection?They use a static method to get the pool instance, getConnection is not static.
Kaj

Standard Business Questions for new FI/CO implementation

Hello,
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Please assist in this reagard as it is very urgent.
Points will be given generously.
Thanks

Hi Ashwin,
Please Find below the some of the general questions asked for a new implementation.
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Please list and give a brief explanation.
4)     Please list all your required payment terms.
5)     For the creation of vendor tolerance groups (price, no quantity) please give appropriate details.
6)     For the creation of automated journal entries, please give a complete overview on the assignment of cost elements to cost centers.
7)     As a preparation on the mapping of the chart of accounts, please prepare a complete list of all required accounts that will have to be assigned to the new number ranges, in the Global Chart of Accounts.
8)     Is there a legal requirement for an alternative chart of accounts for your entity?
9)     Please prepare a complete list of all the common payment methods you have in use
10)     Please deliver a complete list of national bank indicators and codes
11)     Will you need different payment formats for different countries? Please give an overview.
12)     Provide An Organisation Chart (Bring a copy with you)
13)     Provide your Current Chart of Accounts Listing (Bring a copy with you)
14)     Provide a list of Cost Centres
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16)     What types of transactions are typical for each account
17)     Approximately how many transactions are processed daily on each bank account?
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Please assign points if found useful
Regards
Genie

Baseline date in payment terms_reply the question for FI experts

Hy guys,
my problem is this: in payment terms I should want that the baseline date is the date of good receipts instead of the date of invoice receipt and this thing should happen only for a particular society.
In your opinion is it possible to make this ?
I have already made the same question to the MM experts but it seems to be more a FI problem and so I also ask you if perhaps there is a user exit that permit to me to make this.
Thanks in advance for kindness and effort,bye
Maximilian

Hello,
Baseline date is the date from which SAP calculates the due date.
You can configure the terms of payment in transaction code OBB8. Within terms of payment you are required to maintain baseline date.
You can select either one of these:
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2) Document Date: Document date of the invoice
3) Entry Date: Nothing but current date of the entry
4) No Default: In the case of no. default, the system will not propose any base line date, however, the user is forced to enter the base line date.
In case of 1, 2 and 3 the system proposes the baseline date, however, the user will have the privilege to change at the time of posting.
You do not have any other options for baseline date, except the these four date options.
Please let me know if you need further details.
Thanks,
Ravi

Question for the experts... Two ISP's, one home network

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Here is my question: What is the best router out there for joining the two ISP's?
We had a network guy up to our place last year and he used the "netsh" command in DOS on each computer in the network. It worked for a while but I have a feeling this may have been a contributing factor in the current troubles we're having with the EA2700. We have removed two of the older PC's that had these command lines and have added a new laptop and tower, both of which we attempted to replicate the netsh command on but without success... Yes, a noob at this stuff...
I'm in the city today and am wanting to purchase the right unit before I head back into the hinterland. Thanks!

If you are planning to join two ISP's, you need a dual WAN router. EA2700 can't handle that. You might want to check this RV042 from Cisco.
If everyone needs to believe in something, I believe I'll have another beer..

Question for the experts on Video problem

We are away on holidays but didn't want to miss this opportunity to ask for help from the experts. I'm not sure if I have a problem with my motherboard or video card or both. I posted the problem previously but here it is again.
I have an HPE-250f HP desktop computer which has worked well although has not had a lot of use. Shortly after purchasing it I got a real deal on a 17" i7 laptop which has been used much more than the desktop. Yesterday numerous Windows updates were installed and a couple of reboots to complete the installations. On occasion in the past Windows updates have caused issues but am sure they are not the cause of the current problem.
Upon turning on the computer yesterday it sounded like an airplane taking off so pulled the side cover off and it was the fan on the video adaptor that was making all of the noise. I have never heard it anywhere near that loud in the past even when under very heavy usage. In addition there was no video signal so my first thought was the adaptor had died. I took the adaptor out and reinstalled it to make sure it was seated properly however no change. I took the adaptor out again and then uncapped the VGA and DVI connectors that are on the rear of the computer but I did not get a video signal from either of those two outlets either. I don't know whether those ports are enabled on the motherboard or in the BIOS as this computer came with an upgraded video card. Either way there was no video. I have another low end video card here that I don't think was ever used so installed it and again no video. The hard drive seems to be making the normal sounds you would hear when it is booting but again with no video can't really say what is going on.
I am sort of out of ideas as to what to try next as without video you can't see if there are any error messages coming up, whether it is trying to boot or is actually loading Windows.
I don't want to scrap the computer and I guess an option would be to try and find the same motherboard and replace it but I am hoping someone may have some suggestions as to whether there should be video from the built in ports that come capped from the factory. It just seems odd that there is no video from the original card, the built in ports, or a different video card. It is also odd the original video card fan funs flat out when you turn the computer on before it even starts to get warm. If there is a problem with the slot the card goes in one would think the built in ports would still have video but that is assuming they are actually enabled but again don't know if they would be.
If anyone has any suggestions or if anyone knows a reliable place to buy the same motherboard that is in this computer I would appreciate that information.
Thank you

Finally back from vacation and took a bit of time to get caught up from vacation. It appears somehow two threads got started so will continue on with this one as there is more activity here. There is no video from the original video card reinstalled in the computer. There is also no video on either of the integrated ports after removing the caps and removing the battery, and tried two different monitors just to be sure. I have a friend with the same computer and he said there is no setting in the CMOS/BIOS to enable the onboard video so don't know if it has been permanently disabled or not but again no video from either of the integrated ports. Also If there is a speaker on this computer they have done a very good job of hiding it and i have never heard it beep in all the time i have owned it. I know at this link under INTERNAL CONNECTORS it mentions a speaker connection. I would install a speaker for the purpose of troubleshooting but I cannot find a reference anywhere that says which pins are for a speaker so if anyone would know where to find this information I would gladly install a speaker so we could troubleshoot further. http://support.hp.com/us-en/product/HP-Pavilion-Elite-HPE-Desktop-PC-series/4162190/model/4262654/document/c02014355 It is certainly a possibility that one of the updates caused an issue but it would be surprising as these were updates to Windows and not the BIOS, so one would think if the update was causing an issue it would be after the POST and when it was about to start loading Windows. I will try the suggestions listed above to the extent I can without a speaker connected but it would be great if someone can post a manual for the motherboard that mentions which pins or header has the speaker connections so I can install a speaker. I just heard back from my friend that has the exact same conputer and his has no audible beep when it starts either and am sure there is simply no internal speaker on this computer. Thank you

Question for Ali Brown about split partition

Ali:
I thought that I was posting a new topic by changing the subject line but I saw that it didn't work--but it was already up in lights . . . . It's an amazing race, eh? Thanks for your previous reply, glad it's easy to do--please, informa me . . . . While replying to Warren P about his printer issues I saw that you are running a split partition in one of your computers. I have an Imac G4 with 10.1.5/9.22 that perhaps one day I'd like to bring up to 10.3.9, but keeping the OS 9 side intact. Is that a GUI type exercise or did it take a special program? I haven't look at Disc Util in my iMac to see how that might be done, nor have I searched Apple Database . . .. Seeing your hardware info just piqued my curiosity. Any links to info about how to do what you did?? Thanks.
eep

Hi Again eep!
As I posted in the previous topic, my HD is not partitioned.
OS 9 & OS X exist together, and my iMac is Dual-Boot.
When I upgraded from 10.1.5, I did a Simple Update to Panther 10.3.x, and eventually updated to 10.3.9.
Some info in these links:
Mac OS X 10.3 installation (FAQ).
About installation options. Basically the same for Panther 10.3.x.
Tiger is available for purchase at The Apple Store (U.S.).
Panther, is no longer available directly from the Apple Online Store, as Tiger 10.4.x is the most up to date OS.
If you know what to look for, a Full Retail Version, of the Panther Install CDs, or a Full Retail Version, of the Tiger Install DVD, can also be purchased rather inexpensively, at some online Apple retailers, Amazon, eBay, AppleRescue, FastMac, etc.
Be sure not to purchase grey, upgrade or machine specific CDs or DVDs.
Panther is only on CDs, not DVDs.
Unless purchased from AppleRescue, the discs should look exactly like the images in the above links, and not say Upgrade on them.
Additional info in these links.
Using OS X Install CDs/DVDs On Multiple Macs
What's A Computer Specific Mac OS X Release
Software Update, Upgrade: What's The Difference?
Before upgrading to any OS X version, check to see if your Mac needs a Firmware Update.
If one is required, you must start the computer from a Mac OS 8 or Mac OS 9 System Folder on the computer's hard disk, not from a CD, in order to install it.
Once Panther 10.3.x is installed, you can use the 10.3.9 Combo Update, to upgrade to the final version.
If your Mac meets the System Requirements for Tiger, you could also consider installing that.
And then use the PPC 10.4.8 Combo Update, to upgrade to the current version.
Panther System Requirements
Additional Panther System Requirements
Tiger System Requirements
Additionally, "Tiger ships on a DVD, but if your Mac doesn’t have a built-in DVD-ROM player, you’ll need CD media. When you buy Mac OS X Tiger, you qualify to purchase Tiger CDs for only $9.95."
Download the Media Exchange Program Order From Here.
Orders must be mailed by March 19, 2007.
AppleRescue, also sells a Tiger installation set on CD
Shop Carefully, Examine All Documentation, And Good Luck!
ali b

A non-RAC question for the experts: Clusterware + ASM

Hi
We have a 2-nodes cluster in production.
It's an active/passive cluster with a cold failover using SUN Cluster.
There is only one Oracle 10G single-instance database (DB1), running on node #1, that use ASM to access the SAN (it's raw devices).
We want to add a third nodes to move to a 3-nodes cluster, that would have 2 separates single instance Oracle 10g database
node #1: DB1 with ASM (the existing database, existing raw devices)
node #2: cluster passive node
node #3: DB2 with ASM (new additional database, new raw devices)
All nodes are connected to the same SAN.
We' want to use Clusterware instead of SUN Cluster.
The single-instance databases, the listeners and the ASM instances would be protected by Clusterware using "application VIP" (not oracle-vip).
It's not RAC ! but in the future both database might become RAC (but that's not the need today)...
My concern is about ASM !
Do I have to install an ASM instance on each node (just like in RAC) ?
Or may I just configure clusterware to ensure there is only ASM instance running on a node ?
Is it possible to have the ASM instance of node #1 and the ASM intance of node#2 that access the same SAN & raw devices ?
In the case DB1 & DB2 fail over to node#2, the unique ASM instance must see the raw devices of both databases, is this possible ?
Do I have to destroy the curent ASM configuration of DB1 to build the new one, or can I just add new raw devices and share tem across all nodes ?
Thanks for your answers.

Hi,
Thanks for the answer
I found this very interesting doucument but it does not go into enough details about ASM, which is my concern.
I found in the Oracle 11g documentation a statement which say that clustered ASM instances for single instance database do not need to talk each other as long as they do not handle the same diskgroup (Figure 1.3 ; http://download.oracle.com/docs/cd/B28359_01/server.111/b31107/asmcon.htm#i1021337) . Otherwise, it must be clustered. It would also be a problem for me when DB1 and DB2 are on the same node. I would need two different ASM instance, on the same node, which is not a good situation.
What happen when I start an ASM instance on node #3 to access raw devices already in use by node # 2.
I think I need to start from node #1 and change some ASM configuratoion to make it cluster-aware.
Next, I would add a second clustered ASM instance on node #2, and so on, to make sure that all ASM instances of all nodes can access the same diskgroup, and thefore being able to re-use the existing database on node #1 as well as creating a new one one node #2 (all on the same SAN)

(HTTPService - result="" - to ArrayCollection) - a question for super expert ;)

Firstly look at my example then you will read the question:
Look at example below - I'm using HTTPService component to retrieve data from SQL database
(read_record.php is generating nice and tidy xml file with my data)


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        url="http://www.pudelek.pl/SCRIPT/A/read_record.php"
        result="patient(event)">
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Then 'result' is calling a function patient() which task is to assign 'event.result'
to ArrayCollection called 'A_patient_dp' (this ArrayCollection is a data provider
for a specific data grid)
private function patient(event:ResultEvent):void {
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Everything looks great here, data grid shows all the data from xml file generated
by read_record.php
and now is my problem :
I don't want to display all the data, I want HTTPService to retrieve only particular data
which are described by variable {parametr} - this var is generated by my application
I've dond it this way:


    <mx:HTTPService id="readRequestA"
        url="http://www.pudelek.pl/SCRIPT/A/A_send_read_record.php"
            useProxy="false"
            method="POST">
        <mx:request xmlns="">
            <idstaff>{parametr}</idstaff>
        </mx:request>
    </mx:HTTPService>
I'm looking into source of 'A_send_read_record.php' in the internet browser and I see
exact data tree (filtered) which I need.
The problem here is : how to call function patient(event:ResultEvent) and give it
data from the event to be assigned to ArrayCollection - like in first example.
Thanks for all the ideas !!

If this post answers your question or helps, please mark it as such.
Greg Lafrance - Flex 2 and 3 ACE certified
www.ChikaraDev.com
Flex / AIR Development, Training, and Support Services
<mx:HTTPService id="readRequestA"
url="http://www.pudelek.pl/SCRIPT/A/A_send_read_record.php"
useProxy="false" result="patient(event)" method="POST">
<mx:request xmlns="">
    <idstaff>{parametr}</idstaff>
</mx:request>
</mx:HTTPService>

Question for the moderators about KT400/MSI

ive seen the overwhelming number of posts about this mobo, i cant help but wonder. WHEN is msi coming out with a good bios to fix all the memory probs/file transfer probs/ati 9700 probs? ive posted my problem numerous times and everytime i get the PS answer. ive read countless other posts where thats the advice you give the poor soul who also has the same model and problem (misery loves company!!) so they go out and waste more money getting a 500 watt PS and still have the exact same problem. is MSI ignoring their customers? are they listening? do they know how jacked up this chipset is? is their answer going to be "get a bigger PS"? im tired of waiting. im NOT going to fool around with a "BETA" bios either. thats just plain asking for trouble, and i cant afford to have my computer down. it costs me money/time. whats the answer? i am thinking of asking one or two of the bigger hardware/internet news sites this same question. maybe getting that kind of attention would rattle MSI into an answer because they dont seem to be able to answer emails very well... MSI has got to get on the ball.

the bios to fix your hard drive problems is contained in the crc thread above
and most 9700 problems have turned out to be down to which ati revision it was as far as ive read

Retriggerable AI questions for the experts

I am using a PCI-6111 and would like to acquire 2048 points at 5 MHz triggered at 100 Hz. I am trying to use DAQmx.
Question 1:
I downloaded the retriggerable pulse train generation example for analog input and it seems fine except that I need an analog trigger and the counter trigger only allows digital. I modified the code (see attached) so that the analog input task has an analog trigger and then tried using AIStartTrigger as the source for my digital trigger for the pulse train generation. This works sometimes, but not others. Annoyingly when it doesn't work I receive no errors. The check for available samples always returns 0 and I can see the counter is not triggering on a scope (well it changes level once, but never generates a pulse train). I searched around and found another example posted (http://forums.ni.com/ni/board/message?board.id=170&message.id=189503#M189503) where a dummy analog output task is created to get an analog trigger. Instead of using AIStartTrigger they use AnalogComparisonEvent. Using AnalogComparisonEvent in my code instead of AIStartTrigger (but still in the AI task) seems to work fine. Is there a reason I shouldn't be using AIStartTrigger?
Question 2:
It seems that if my buffer is too small I get a similar sort of problem. That is, I receive no errors, the available samples always return 0, and the counter never triggers. In the retrig pulse generation example there is a cryptic remark about making the buffer 1000 points bigger than you need. I find I generally need something more like 10x points if I purposely try to slow down the system by moving a window around, for example. My question, though, is why do I not receive an error message and/or is there something I can check that will tell me there is a problem? I think the problem has something to do with the buffer being overwritten before the first check, but I'm not sure...
Attachments:
Multi-Function-Ctr Retrigg Pulse Train Generation for AI Sample Clock Mod.vi ‏182 KB

Hello Phamton,
To answer your questions:
1. I know that using the AnalogComparisonEvent is the typical way to trigger a counter off of an analog signal. The is the generally recommended method because the AnalogComparisonEvent comes straight from the analog comparison circuitry, however, the ai/StartTrigger signal should also work to start your counter task. If this approach was not working sometimes, I would first suspect the signal that was connected to the trigger line, and whether or not it was actually meeting the trigger condition at those times. Have you tried connecting a scope to the analog trigger signal when your program is not working?
2. I'm not sure of the exact reasoning for that comment in the example code, but even still, if you task is not starting, I would first suspect the actual analog signal that is being used as the trigger. Connect it to a scope and make sure that it is meeting the trigger condition when you run that program.
In any case, if your analog input task never receives the start trigger, you should get a timeout error. Let me know if you have any further questions about this issue.
Best regards,

Question for ORACLE EXPERTS!!! PERFORMANCE PROBLEM!!!

I have 2 nodes on RAC. On node1 the following query run in 15 seconds and on node2 the same query run in 40 minutes. This is a big problem because we are migrating a SQL Server database to Oracle RAC 10gR2 (10.2.0.2) on HP-UX Itanium and we can´t finish the project because of this performance problem!!! PLEASE HELP ME ORACLE GURUS !!! I have opened a TAR at Metalink a 3 month ago,but they can´t help me with this. Can anyone explain this event to me please??? " gc cr multi block request 92011 0.33 737.49
This is the query that i run on both nodes and this is the tkprof of the trace file when i run this on second node:
select /*+ NO_PARALLEL(t) */ sum(t.saldo_em_real)
from
brcapdb2.titulo t
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 1 13.76 790.26 0 107219 0 0
total 3 13.76 790.26 0 107219 0 0
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 31
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 2 0.00 0.00
SQL*Net message from client 2 0.02 0.02
gc cr multi block request 92011 0.33 737.49
gc current grant busy 1 0.00 0.00
latch: KCL gc element parent latch 4 0.00 0.00
latch: object queue header operation 17 0.00 0.01
latch free 6 0.00 0.00
gc remaster 9 1.94 9.00
gcs drm freeze in enter server mode 19 1.97 30.52
gc current block 2-way 10 0.61 2.72
SQL*Net break/reset to client 1 0.01 0.01
Please help me if you can!!
Tks,
Paulo.

Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 2 0.00 0.00
SQL*Net message from client 2 0.02 0.02
gc cr multi block request 92011 0.33 737.49
gc current grant busy 1 0.00 0.00
latch: KCL gc element parent latch 4 0.00 0.00
latch: object queue header operation 17 0.00 0.01
latch free 6 0.00 0.00
gc remaster 9 1.94 9.00
gcs drm freeze in enter server mode 19 1.97 30.52
gc current block 2-way 10 0.61 2.72
SQL*Net break/reset to client 1 0.01 0.01There's lots of global cache traffic going on. All those multiblock transfers seem to be saturating the interconnect. Some things to consider:
- Have a look at metalink note 3951017.8 for a possible fix
- Check that your interconnect is properly configured
- Try running the query with PARALLEL hint. This would mean doing disk I/O instead of buffer & interconnect I/O.
edit: changed "without NOPARALLEL" to "with PARALLEL"
Message was edited by:
antti.koskinen

Question for Database EXPERTS about implementing an Embedded Database

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