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13-Sep-19 10:27

I'm considering writing a B+ tree in C# but in order to make it worthwhile it needs to be disk backed.

My question is, and it's a weird one but i have my reasons:

Did Btrieve use separate files for its indexes versus its data or was it all in one file?

When I was growin' up, I was the smartest kid I knew. Maybe that was just because I didn't know that many kids. All I know is now I feel the opposite.

modified 13-Sep-19 16:39pm.

User 1106097913-Sep-19 10:40

User 11060979

13-Sep-19 10:40

I remember it very good. Everything was in _one_ file.

It does not solve my Problem, but it answers my question

modified 19-Jan-21 21:04pm.

honey the codewitch13-Sep-19 10:40

13-Sep-19 10:40

Thanks! You just helped me understand ISAM a lot better than you maybe know you did. Big Grin | :-D

When I was growin' up, I was the smartest kid I knew. Maybe that was just because I didn't know that many kids. All I know is now I feel the opposite.

User 1106097913-Sep-19 10:44

User 11060979

13-Sep-19 10:44

You are welcome Big Grin | :-D

I don't think this was a important help. Btw way some details e.g. here: Btrieve Files[^]

It does not solve my Problem, but it answers my question

modified 19-Jan-21 21:04pm.

honey the codewitch13-Sep-19 10:45

13-Sep-19 10:45

it was because it told me how records are managed and a bit about how they're stored. Thanks for the format. I'm not looking to read BTrieve files but I'll save the link because it may answer questions that come up.

My primary interest in ISAM is in how it maps a B+ tree structure to disk, because that's what I'd need to do with a B+tree implementation.

When I was growin' up, I was the smartest kid I knew. Maybe that was just because I didn't know that many kids. All I know is now I feel the opposite.

k505413-Sep-19 15:06

k5054

13-Sep-19 15:06

honey the codewitch wrote:
My primary interest in ISAM is in how it maps a B+ tree structure to disk, because that's what I'd need to do with a B+tree implementation.

You could always take a look at either gnu GDBM or Oracle-Berkeley DB to see how they solved the issue. Unless that's cheating, or you want to avoid any license issues.

honey the codewitch13-Sep-19 15:13

13-Sep-19 15:13

yeah i don't even want to touch anything GNU

besides, that code is mature. it's not so easy to dissect.

I'd rather either start from scratch, or from something simple.

When I was growin' up, I was the smartest kid I knew. Maybe that was just because I didn't know that many kids. All I know is now I feel the opposite.

Re: Does anyone here remember BTrieve? (old DOS one and its variants)

Randor 13-Sep-19 18:19

Randor

13-Sep-19 18:19

k5054 wrote:
You could always take a look at either gnu GDBM or Oracle-Berkeley DB to see how they solved the issue. Unless that's cheating, or you want to avoid any license issues.

Those DBM libraries simply work in a contiguous memory region and write the entire database back to disk when saved. That's why everyone avoided key-value-store (NoSQL is the new buzzword) databases for over a decade. When RAM became cheap and you build a server with terabyte of RAM... the old things became new again.

By the way... let's give credit to the inventing author... Ken Thompson[^] who wrote the first DBM implementation... sometime in the late 1970's. It's not even mentioned in his wikipedia bio... I wonder if anyone will remember that in 30 years.

Best Wishes,
-David Delaune

Scientiæ de conservata veritate.

Ron Anders13-Sep-19 10:57

Ron Anders

13-Sep-19 10:57

I do. The worlds DOS speed demon data systems used it.

RDP (Resort Data Processing) software was one. Ran on Novell Servers.

And we made a lot of money then.

Re: Does anyone here remember BTrieve? (old DOS one and its variants)

Marc Clifton13-Sep-19 12:42

Marc Clifton

13-Sep-19 12:42

honey the codewitch wrote:
Did Btrieve use separate files for its indexes versus its data or was it all in one file?

On systems with dual floppies, we sometimes implemented the index on one file one one floppy and the data on another. Smile | :)

But those were dedicated turnkey systems on a 32KB machine with 720KB floppies (dual sided.) Laugh | :laugh:

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Re: Does anyone here remember BTrieve? (old DOS one and its variants)

honey the codewitch13-Sep-19 16:24

Most annoying marketing tactic?

13-Sep-19 16:24

That's actually a smart way to do it in any case - even if you had the space on one disk.

The reason is, as long as the floppy controller supported it, you could have both spindles working at once, and so you don't have as much I/O lag.

The same principle applies in modern databases and is why good database design will partition frequently accessed tables onto their own HD "spindles" - either physical spindles, or just logical like with an SSD - point is, you read from more than one drive at once.

When I was growin' up, I was the smartest kid I knew. Maybe that was just because I didn't know that many kids. All I know is now I feel the opposite.

Chris Maunder13-Sep-19 9:28

Chris Maunder

13-Sep-19 9:28

I think my new pet peeve are those sites that change their Window title to "(1) New Message" at 1Hz so that, even when they are a background tab they are still annoying you.

Make mental blacklist note, close tab, get on with my work.

cheers
Chris Maunder

Re: Most annoying marketing tactic?

OriginalGriff13-Sep-19 20:06

OriginalGriff

13-Sep-19 20:06

Never mind a mental blacklist - add 'em to your adblock list and never see it again.

There aren't many sites out there that are indispensable - CodeProject is obviously one of those - so if they are annoying, block 'em, maybe tell 'em why, and move on.

Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!

okay. I ... really like TypeScript

honey the codewitch13-Sep-19 9:16

13-Sep-19 9:16

I just ported a splay tree function from typescript to C# painlessly and it made my code faster.

this is amazingly and wonderfully not like javascript.

it's a wonder everyone is not using it instead of raw JS.

When I was growin' up, I was the smartest kid I knew. Maybe that was just because I didn't know that many kids. All I know is now I feel the opposite.

Chris Maunder13-Sep-19 9:25

Chris Maunder

13-Sep-19 9:25

Yeah - I've found TypeScript and never want to go back.

Our own @Pete-OHanlon has written a book on the topic. It's a lifesaver.

cheers
Chris Maunder

Advanced TypeScript Programming Projects

Pete O'Hanlon13-Sep-19 9:38

Pete O'Hanlon

13-Sep-19 9:38

Thanks, Chris. The beer's on me Smile | :)

I have to admit, I am very fond of TypeScript. The more I use it, the fonder I am. So much so, I'm currently writing my second TypeScript book.

honey the codewitch13-Sep-19 9:53

13-Sep-19 9:53

cool!

When I was growin' up, I was the smartest kid I knew. Maybe that was just because I didn't know that many kids. All I know is now I feel the opposite.

Marc Clifton13-Sep-19 12:43

Marc Clifton

13-Sep-19 12:43

Pete O'Hanlon wrote:
So much so, I'm currently writing my second TypeScript book.

Very cool!

Latest Articles:
Fun Exploring Div and Table UI Layout

Slacker00713-Sep-19 10:03

Slacker007

13-Sep-19 10:03

Is this the book you are referring to. Cause it looks like it could be the one. I'm buying it if it is.

https://www.amazon.com/Advanced-TypeScript-Programming-Projects-JavaScript/dp/1789133041[^]

Edit: It has to be his bio on Amazon mentions CodeProject. I just bought it. Partly because I am new to typescript, and second, Pete wrote it.

modified 13-Sep-19 16:09pm.

Advanced TypeScript Programming Projects

Pete O'Hanlon13-Sep-19 10:27

Pete O'Hanlon

13-Sep-19 10:27

'Tis the one. And I thank you.