Format vs Erase: What is the difference? OK a really basic question: what is the difference between formatting and/or erasing a memory card? Is it necessary to do both?

flashbang

OK a really basic question: what is the difference between formatting and/or erasing a memory card? Is it necessary to do both?

rmalarz Loc: Tempe, Arizona

It's not necessary to do both. Format works just fine. The difference is, erase actually leaves the file there, but changes the first character so that the system doesn't see it. Format removes the files pretty completely by overwriting with 0s and 1s randomly.
--Bob

flashbang wrote:

OK a really basic question: what is the difference between formatting and/or erasing a memory card? Is it necessary to do both?

rgrenaderphoto Loc: Hollywood, CA

There is an "address book" as part of any storage device allocation table that contains the sector location of any stored files. Erasing or deleting something removes the address from the table, making the sectors available for storage. The file is still there, and can be recovered by utilities that will put the address back in the allocation table.

Formatting generates a completely new file system, overwriting the existing table, making your data unrecoverable.

LFingar Loc: Claverack, NY

flashbang wrote:

OK a really basic question: what is the difference between formatting and/or erasing a memory card? Is it necessary to do both?

One thing to keep in mind: If you format a device, whether a memory card or a hard drive, programs such as Recuva will not be able to recover any files if you should suddenly find that you need them. Erasing, or deleting will allow recovery. I almost always format, but I make darn sure my files are properly backed up. Also, with Canon and possibly others, doing what Canon calls a deep format vs a quick format will restore full write speed to the card. Canon writes its data differently then most others making a full format desirable periodically. Otherwise, it doesn't make any difference to your camera. It will simply overwrite the old data the same as the hard drive in your computer does.

Longshadow Loc: Audubon, PA, United States

Erasing removes the file name from the FAT table (file allocation table) and makes the space it used available for use. The file itself remains on the disk (or memory chip) until written over by another file. Formatting annihilates the file contents and empties the FAT table.

Rongnongno Loc: FL

flashbang wrote:

OK a really basic question: what is the difference between formatting and/or erasing a memory card? Is it necessary to do both?

Very little:
Format erase the part of the drive that contains information as to where the files are. (Essentially erase everything)
Erase or delete set on bit, telling the drive that the space is now free.

In both cases, if the free space has been written over some of the data will not be recoverable unless you use a specialized program that can read any number of layers under the existing data...

Recuva CAN recover data from a formatted drive

Recuva web site wrote:

Similarly, when you format a drive (especially if you use the Quick Format option), Windows erases the hidden index but does not overwrite the existing files until you start saving new data to it. Recuva can still scan the drive's contents to find your files.

Now you have low format among other options that are destructive but almost ALL data can be recovered if your pockets are deep enough.

Rongnongno Loc: FL

rmalarz wrote:

It's not necessary to do both. Format works just fine. The difference is, erase actually leaves the file there, but changes the first character so that the system doesn't see it. Format removes the files pretty completely by overwriting with 0s and 1s randomly.
--Bob

Only if you use 'secure format'.

CHG_CANON Loc: the Windy City

flashbang wrote:

OK a really basic question: what is the difference between formatting and/or erasing a memory card? Is it necessary to do both?

If you have multiple and different cameras and share the cards between the cameras, format the card in the camera prior to each use. Otherwise, it doesn't matter on erase vs format for a card used over and over in the same camera.

rmalarz Loc: Tempe, Arizona

You are basically very correct. However, there are way of recovering even formatted files. But, that is not a topic for discussion based on the OP's question.
---Bob

LFingar wrote:

One thing to keep in mind: If you format a device,... (show quote)

jerryc41 Loc: Catskill Mts of NY

rmalarz wrote:

It's not necessary to do both. Format works just fine. The difference is, erase actually leaves the file there, but changes the first character so that the system doesn't see it. Format removes the files pretty completely by overwriting with 0s and 1s randomly.
--Bob

Clapperboard

Neither FORMAT nor ERASE actually removes the data. That is why the police can recover files from villains computers.
Erase deletes the filing system record of particular files. Format deletes the filing system of all the files. The data is still there and can be recovered by programmes that access data on a 'Bit' by 'Bit' process. That is how you can still salvage files even after formatting, but before recording anything new to the card/drive/whatever. If something new has been recorded it may have written over the original data.

LFingar Loc: Claverack, NY

rmalarz wrote:

You are basically very correct. However, there are way of recovering even formatted files. But, that is not a topic for discussion based on the OP's question.
---Bob

Thanks. I probably should have stated that for the average person a full (or low as Ron mentioned, not deep as I mentioned) format is the end of the road as far a recovery with the free and low priced Internet recovery programs are concerned. Then it is time to shell out money for more sophisticated programs or professional services.

markngolf Loc: Bridgewater, NJ

rmalarz wrote:

It's not necessary to do both. Format works just fine. The difference is, erase actually leaves the file there, but changes the first character so that the system doesn't see it. Format removes the files pretty completely by overwriting with 0s and 1s randomly.
--Bob

Great clarity!!
Mark

photoman022 Loc: Manchester CT USA

This article (which I referenced a year ago on UHH) explains the necessity of formatting. I hope it answers your question.

http://www.diyphotography.net/not-delete-images-memory-card-using-camera/?utm_source=DIYP+Weekly+Newsletter&utm_campaign=9ed603026a-EMAIL_CAMPAIGN_2016_12_15&utm_medium=email&utm_term=0_4d53c6b51c-9ed603026a-99463617&mc_cid=9ed603026a&mc_eid=9e8576b5c1

stuparr935 Loc: Dallas, Texas area

After formating of a memory card in you Camera only the VTOC (visual table of contents) is rebuilt/re-created and until you take another photo, all your images can be restored with special software. When you erase an image file in camera, you are deleting the image from the VTOC and may not free up the entire image files space thus may fragment the memory on the card a bit. A fragmented memory card just means, in this case, that there is less free memory space on that card to store more images files. A picture just taken and erased may return all that image files storage space for additional images to be taken, but better to delete image files after up loaded into your computer.... remember to format, not erase, all image files in your camera to reuse the storage card...