I recently purchased a sandisk memory stick pro and a creative muV0 Tx 512mb mp3 player.

the memory stick i got is only 468mb in capacity and the mp3 player is only 490mb, i wrote to them complaining of this and they told me:

“These slight shortfalls in capacity are quite normal. They may refer to the maximum manufacturer capacity in testing, but not consistantly.”

Is this correct, surely not?!

[quote author=“diego”]I recently purchased a sandisk memory stick pro and a creative muV0 Tx 512mb mp3 player.

the memory stick i got is only 468mb in capacity and the mp3 player is only 490mb, i wrote to them complaining of this and they told me:

“These slight shortfalls in capacity are quite normal. They may refer to the maximum manufacturer capacity in testing, but not consistantly.”

Is this correct, surely not?!

Yes it is.

Discrepancy Between Reported Capacity and Actual Capacity
Many customers are confused when their operating system reports, for example, that their new ST310240A 10.24-Gbyte hard drive is reporting only 9.85 Gbytes in usable capacity. Several factors may come into play when you see the reported capacity of a disc drive. Unfortunately there are two different number systems which are used to express units of storage capacity; binary, which says that a kilobyte is equal to 1024 bytes, and decimal, which says that a kilobyte is equal to 1000 bytes. The storage industry standard is to display capacity in decimal. Even though in binary you have more bytes, the decimal representation of a Gbyte shows greater capacity. In order to accurately understand the true capacity of your disc drive, you need to know which base unit of measure (binary or decimal) is being used to represent capacity. Another factor that can cause misrepresentation of the size of a disc drive is BIOS limitations. Many older BIOS are limited in the number of cylinders they can support.

Motivation for Proposed Prefixes for Binary Multiples
Once upon a time, computer professionals noticed that 1024 or 210 (binary) was very nearly equal to 1000 or 103 (decimal) and started using the prefix “kilo” to mean 1024. That worked well enough for a decade or two because everybody who talked kilobytes knew that the term implied 1024 bytes. But almost overnight a much more numerous “everybody” bought computers, and the trade computer professionals needed to talk to physicists and engineers and even to ordinary people, most of whom know that a kilometer is 1000 meters and a kilogram is 1000 grams.

No memory based device (hard drive or other) gives you the full amount of useable storage.

Erik

but surely they can’t supply something almost 80mb less than specified on a 512mb device? that’s like needing to buy an extra 64mb card to make up for it.

[quote author=“diego”]but surely they can’t supply something almost 80mb less than specified on a 512mb device? that’s like needing to buy an extra 64mb card to make up for it.

Yes…your also comparing pre-formatted to post-formatted…2 different #s.

Go pick up a 160GB HD…youll get about 152GB of useable space…thats 8GB missing…

Erik

8gb! holy cow… hahaha

i guess i forgot how much fat/NT/Fat32 filesystems use.

i must be living in the stone ages when 40 megs was killer.

is the lost memory used for indexing by the OS?  i think my computer IQ has taken a huge drop since high school

Here’s a quick explanation…

Formatting creates multiple tracks with multiple sectors within each track. Because the sectors must be a fixed size (bytes), it’s possible for waste to occur. For instance, if sectors are 4Kb in size and you save a file that’s only 1Kb, then you lose the rest of that space. A 5Kb file will use 2 sectors (8Kb). So, that will also explain for the loss of space.

NTFS itself also takes up some of the space because it reserves MFT space for security descriptions and for its journaling files system. This is to ensure that there’s less chance of data loss in the event of power failure during the writing of data.

is NTFS more efficent than fat32? or is just a reliability issue?

[quote author=“jso902”]is NTFS more efficent than fat32? or is just a reliability issue?

No, it’s not. In addition to being journaled, it also allows permissions, compression and encryption - all of which incur some overhead. FAT is a much older and simpler file system format, but it has some significant limitations especially in terms of volume size.

[quote author=“jso902”]is NTFS more efficent than fat32? or is just a reliability issue?

In my opinion, NTFS is more efficient and more resistant to corruption in my experience.

Yeah, I reciently bought a 200 GB Seagate 7200.7 for my desktop and I actually get 186 GB of useable space, a 14 GB loss. For some people, that larger than their whole hard drive! I use NTFS, in case anyone wanted to know.

It’s not just that. Hard drive and flash drive manufacturers aren’t completely honest about what “giga” means. They’re using the metric definition which means 1,000,000. In computer terms, a gigabyte is 2^20 bytes (1,048,576 bytes). At least that’s the official excuse… Even though they’re officially the same capacity, you’ll find a relatively large variation in formatted capacity, even with the same file system.

Basically it boils down to the fact that they lie.

[quote author=“Drachen”]Basically it boils down to the fact that they lie.

Yup…and the first hard drive maker to put the ‘actual’ capacity on the drive is the first one to have their drives sit on the shelf.

Too bad they can’t all agree to use the real capacity…

Erik

Of course, with the types of deals they have on the really large products, I really don’t care that much anymore. If my $69 (as of this weekend’s Fry’s deal) Seagate 200GB drive is only giving me 186GB I can’t say that I lose much sleep over it.  Yeah….$69 for the 5 year warranty/retail box version. It’s ridiculous!

[quote author=“gr00vy0ne”]Of course, with the types of deals they have on the really large products, I really don’t care that much anymore. If my $69 (as of this weekend’s Fry’s deal) Seagate 200GB drive is only giving me 186GB I can’t say that I lose much sleep over it.  Yeah….$69 for the 5 year warranty/retail box version. It’s ridiculous!

Well, flash will be around that price very soon too…I think we are at $80 for 1GB CF card… (Just teasing TS)

Yeah, it seems like it doesn’t really matter anymore, its just annoying when you sit back and think of the lost GB that could be filled with other things…

Erik

[quote author=“gr00vy0ne”]
Formatting creates multiple tracks with multiple sectors within each track. Because the sectors must be a fixed size (bytes), it’s possible for waste to occur. For instance, if sectors are 4Kb in size and you save a file that’s only 1Kb, then you lose the rest of that space. A 5Kb file will use 2 sectors (8Kb). So, that will also explain for the loss of space.

Well… almost. For memory technology devices, like USB sticks and other types of flash memory, there of course are no tracks. There may be sectors (there almost certainly are) and there may even be some kind of “emulated tracks” (i.e. for PCMCIA/Cardbus Flash Cards that simulate an IDE harddisk), but even then - or even on true disks with true tracks and true sectors - the sector size isn’t necessarily related to the chunk size of the filesystem.

And that’s the important thing: how the filesystem organizes the data. Let’s take FAT for example. In FAT, the smallest allocation unit is called a “cluster”. That cluster size can be totally different from the sector size. You may specify this while creating the filesystem, e.g., you may specify a cluster size of 16384 bytes or just 4096 bytes. The sector size of most media, however, is 512 (or 2048 for data CDs, flash sometimes has 256 bytes).

Most filesystems behave the same. I believe I heard that ReiserFS doesn’t use any kind of chunk, so that a 2 byte file really just uses up 2 bytes (+ metadata), but I didn’t verify this.

NTFS itself also takes up some of the space because it reserves MFT space for security descriptions and for its journaling files system. This is to ensure that there’s less chance of data loss in the event of power failure during the writing of data.

Yes, and even more. Every read/write filesystem basically has tons of metadata. FAT has a huge File Allocation Table, a FAT (that’s why FAT is called FAT, because it has a fat FAT).

That said: the larger the media, the larger the metadata, the greater the loss. But not relatively. Most of the time, the loss stays in the same percent range.

Julien