Empty 512MB CF card shows only 487.47 free?

bmorisette · 08-08-03, 01:20 PM

Hi there,

Just got my brand new 512MB CF card direct from Kingston (Japanese made), but when I go into system memory screen it shows the free memory as only 487.47MB. What's the deal?
Is my CF card defective?
Is this a DELL hardware issue?

I got an X5 Advanced with 2003. I have build A05 which installed after downloading from the FTP site (not hacked, I had an Axim that shipped with A04).

Thanks in advance for the help.

Barney

nemattoad · 08-08-03, 01:32 PM

I believe its natural, its the way the File system works, try reformatting it to FAT16

smeg36 · 08-08-03, 01:38 PM

Yeah, no matter what format you put it in (FAT16, FAT32) you aren't going to get the full 512 MB. Just like on a computer when you have 512 MB of RAM, your system can't use all of it, when you have 512 MB of CF, your Axim can't use all of it.

08-08-03, 02:01 PM

Sorry, but you are all wrong. Advertised storage size is computed differently than how the computer views it.

Here is an excellent explanation I found for this.

Storage is advertised as 1,000 bytes = 1KB. However, computers actually consider 1,024 bytes = 1KB.

Real Storage
8 bits = 1 byte.
1,024 bytes = 1 kilobyte (KB).
1,024 KB = 1 megabyte (MB)
1,024 MB = 1 gigabyte (GB)
1,024 GB = 1 terabyte (TB)

In the marketing world,
1,000 bytes = 1 KB
1,000 KB = 1 MB
1,000 MB = 1 GB
1,000 GB = 1 TB

So, if you do the math:

A storage card advertised as 512MB has the following number of bytes:
512,000,000 bytes
or 500,000 kilobytes
or 488.28 MB

A storage card advertised as 1024MB has the following number of bytes:
512,000,000 bytes
or 1,000,000 kilobytes
or 976.56 MB

A Drive advertised as 100GB has the following number of bytes:
100,000,000,000 bytes.
or 97,656,250 kilobytes
or 95,367 MB
or 93.13 GB

Basically, the bigger the card or drive the more space you are "losing".
.9765 bytes -> kilobytes (KB) a loss of 3% of advertised capacity.
.9536 KB -> Megabytes (MB) a loss of 4.7% of advertised capacity.
.9313 MB -> Gigabytes (GB) a loss of 6.8% of advertised capacity.
.9094 GB -> Terabytes (TB) a loss of 9.1% of advertised capacity.
.8882 TB -> Petabytes (PB) a loss of 11.1% of advertised capacity.
.8674 PB -> Exabytes (EB) a loss of 13.3% of advertised capacity.
.8470 EB -> Zettabytes (ZB) a loss of 15.3% of advertised capacity.
.8272 ZB -> Yottabytes (YB) a loss of 17.3% of advertised capacity.

Leave it to the marketing guys to come up with such a confusing system!!!

08-08-03, 02:20 PM

Glad I could help!

By the way, nice signature!

smeg36 · 08-08-03, 02:51 PM

Well E B, that is odd isn't it. My 512 MB Toshiba CF has 501.24 MB of available space. So doing your math doesn't add up for mine. I wonder why. Any ideas?

Howard2k · 08-08-03, 03:03 PM

The math isn't always exact because there IS also a little overhead for FAT16/FAT32 and the vendors may not stick with exactly 512,000,000 bytes.

I'd quit complaining and just accept it :)

E B's post is right on the money.

08-08-03, 03:10 PM

E B,

I disagree with your explaination of things. I am not sure where your information comes from either.

I am an engineer, and have been in software engineering for over 10 years (my credentials).

I have never heard in engineering anyone say 1 KB is 1000! All engineers I have ever worked with say 1 KB is 1024.
It comes from base 2 numbering system, (binary, the 1s and 0s in the comuter world).

2 to the power of 10 = 1024 = 1 KB.

If you follow this you can probably jot out MB, GB and so on.

The reason you don't get the full advertised capacity of these devices is they have overhead to keep track of what is located where (just like hard drives).

The reason you lose more as your capacity increases (you loose more with 1 GB than 1 MB) is more complicated.
Memory used in this manner is divided into sectors. You can only create so many sectors (based on how the device is formatted - FAT16 or FAT32 - and the operating system).

If you are only allowed enough sectors so that on a 1 MB device you get 1 KB sized sectors (if you have 1 KB number of sectors; 1024 * 1024), you will have bigger sectors (because you get the same number) on a larger capacity device.
If you had a 10 MB device with the same number of sectors they would be tens times larger, 10 KB sized sectors.

If the device needed 1 KB for its overhead,
the 1 MB device allocates 1 sector, which is 1 KB;
but for the 10 MB device, it allocates 1 sector (it has to allocate the entire sector), which is 10 KB.

08-08-03, 03:26 PM

Quote:

Originally posted by uzziah0
E B,

I disagree with your explaination of things. I am not sure where your information comes from either.

I am an engineer, and have been in software engineering for over 10 years (my credentials).

I have never heard in engineering anyone say 1 KB is 1000! All engineers I have ever worked with say 1 KB is 1024.
It comes from base 2 numbering system, (binary, the 1s and 0s in the comuter world).

2 to the power of 10 = 1024 = 1 KB.

If you follow this you can probably jot out MB, GB and so on.

The reason you don't get the full advertised capacity of these devices is they have overhead to keep track of what is located where (just like hard drives).
The reason you lose more as your capacity increases (you loose more with 1 GB than 1 MB) is more complicated.
Memory used in this manner is divided into sectors. You can only create so many sectory (based on how the device is formatted - FAT16 or FAT32 - and the operating system).
If you are only allowed enought sectors so that on a 1 MB device you get 1 KB sized sectors (if you have 1 KB number of sectors; 1024 * 1024), you will have bigger sectors (because you get the same number) on a larger capacity device.
If you had a 10 MB device with the same number of sectors they would be tens times larger, 10 KB sized sectors.

If the device needed 1 KB for its overhead,
the 1 MB device allocates 1 sector, which is 1 KB;
but for the 10 MB device, it allocates 1 sector (it has to allocate the entire sector), which is 10 KB.

I got those exact numbers from somewhere else (not from my own head). I can't find the exact reference, but I did a quick search and found this info on Adaptec's site: ASK Adaptec - look at answer #4.

Although what you say is true (1K = 1024), the hard drive marketers seem to want to ignore that fact.

08-08-03, 04:55 PM

Thanks for the link to your source.

I would have to say that I have never seen someone that is knowledgable explain this that way.

I cannot explain why they say what they do, but if you went to a Tech message board, I'm guessing your get lots of disagreements.

You could go over to ExtremeTech (www.ExtremeTech.com) and see what they have to say about this explaination.

JakeRich · 08-08-03, 05:01 PM

Engineering world 1 MB = 1024*1024 or 1,048,576
Marketing world 1 MB = 1,000,000

So for 512 the difference between marketing world and engineering world is 48,576 * 512 or 24,870,912.

So Engineering world - Marketing world makes a 512 card come out about 24.87 Meg less, or 487.13. The minor difference may be in that even Marketers underestimate the overstatement!

08-08-03, 05:14 PM

Quote:

Originally posted by uzziah0
I cannot explain why they say what they do, but if you went to a Tech message board, I'm guessing your get lots of disagreements.

Not sure what there is to disagree with - it's fact.

Now if you want to disagree with the hard drive manufacturers, I would be all for that. However, right now that is the standard for measuring storage devices. So imagine trying to get the whole storage industry to change just because we disagree with them. Plus, if any of the manufacturers were to change, they would be at a disadvantage and have to explain why their 100GB drive is really bigger than the competition's and is worth paying more for. Think of the whole Intel/AMD mess over processor clock speed.

nemattoad · 08-08-03, 05:17 PM

The rating <xxxx+> amd assigns to their CPUs instead of a <x.xghz> in their titles is actually the relative performance when compared to the older thunderbird line of CPUs, not intel.

However, before the 533mhz FSB for P4s became avaliable, it could be used to compare against P4s as well.

A little tidbit of info from the nemattoad :D

Howard2k · 08-08-03, 06:27 PM

1k IS SUPPOSED to be 1024. The marketers are wrong but it's still the way that storage media is measured.

Uzziah0. You're partially right in that respect. You're also right that there is overheard for FAT etc.

But the BIGGEST issue is the 1024/1000 issue. It's a well documented fact.

Claritin · 10-05-03, 12:00 AM

I have been a Professional PC tech for umm... 9 years I think now. I have been building my own systems since I was like 12 (for 17 years)

1000k per meg vs 1024k per meg is the reason for the bulk of the size descrepency.

Yes we all know it's 1024... we are not the retards... the retards are the ones in marketing labeling the boxes.

I recently bought a 200 Gig Western Digital Drive with 8 meg cache (special edition) ATA-133 (I think... I forget since my MB in my server only supports ATA-100) and 7200 RPM.

My 200 gig drive is about 186 gig in the computing world. It's only 200 gig in the Marketing world.

No one can tell me it takes 14 GIG to keep the FAT table straight LOL.

Also all here are more hard drive facts :
1.) The phrase low level formatting doesn't exist in the modern PC world. People still say it but it's just stupid. Low level formatting was how you got your hard drive controller to "map" the actual hard drive. Modern hard drives have the "mapping" part of the controller ON THE DRIVE NOW. It's been this way for a long long time.
2.) Hard drives still map out bad sectors... but with the way the controllers are set up now when you get a bad sector teh controller locks that sector out and remaps it to a sector on a "hidden" section of the drive. so say sector 1268 is dead if your machine tries to write to it the controller will re-direct the data to sector 9678.
3.) All hard drives are shipped with bad sectors that are already redirected by statement #2.
4.) Looking at #3 you can see a "200 marketing GIG" is probably actually "201 Marketing gig" to account for these errors. We are lucky they are too stupid to realize this or we would be paying for "201 Marketing GIG drives" rather than 200.
5.) Putting a HD with alot of bad sectors as a secondary drive and loading your OS off the new drive gives you a higher rate of success on getting files off the drive. Running scan disk or defrag on a drive you KNOW is failing usually does more damage than good... the strain is usually more than the drive can bear.
6.) If your hard drive is completely dead and not under warrenty... try sticking it in the freezer wrapped in a paper towel for 5 mins then re-installing it ASAP powering it up and copying the most important data to another drive ASAP. Sometimes (2% likelyhood if I had to stick a number on it) this will work. While I am not sure of the real logic to it... in techie urban legends it has been said that it cools the controller chips if they are over heating.. and also that the HD platter shrinks a tiny amount... either could be legit... all I know is it works on rare occasion.

(most of the hard drive info was just put here to let you know I am not some reject who claims to be any profession that would back-up his post... I really am a tech (under paid one at that

).... I know HD info is completely irrelevant to the AXIM)