Next year will see 100GB SSD cheap as chips, but why does Linux need to format an SSD?

an SSD?

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Any storage medium needs formatting, since each filessytem type stores
information in different ways on the medium. And you sure would not want
to use FAT with all its limitations as a universal filesystem.

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Does anyone format RAM?

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Are you a Snit?

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abuse complaints to: abuse@eternal-september.org

Are you an internet troll impersonating Peter Köhlmann again?

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Idiot

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Oops........How harsh against your Mr. president of COLA?, an "intelligent
and insightful" leader of COLA, according to Chris Ahlstrom!

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Ahlstrom is a suck up.
Kohlmann is not.

["Followup-To:" header set to uk.comp.os.linux.]

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Yes. Every operating system formats ram so it can find where in the
world the program are that it has to page in, and where the data is,
etc. That that formatting goes on internally to the operating system and
is not a separate process is irrelevant for this discussion.

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In general, embedded systems don't format RAM.
The smaller the system, the less likely.

(e.g. you would have to be seriously stupid to store
 "Hello World" in a text file in FAT formatted RAM.)

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Is this one of those troll posts? I can only assume it is because you're
exhibiting levels of ignorance I thought impossible even for you or
Gortard.

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So what do you call the process of making a RAM filesystem, for
/tmp or /dev, or whatever?

Phil

I'm not sure who said this, but please define "formats ram"

or is this a joke ??

["Followup-To:" header set to uk.comp.os.linux.]


It is partly a joke and partly serious. The operating system must have
tables which tell it where things are-- memory, programs, data, drivers,
... That is want a format is, a formal setup about how one finds stuff
on a disk drive. Just such a formal setup is also needed for ram. Now on
a disk that format is set up once when the disk is readied for storing
data. In ram it is set up when the operating system boots ( and
dynamically while it runs). But in either case, there needs to be a
formal setup allowing things to be found.

 

That is the principle method of using RAM.

SSD is not much more different.

So somewhere in the annals of history, its all gone wrong.

SSDs being memory that retain data after power down,
some additional work needed to extend the RAM model to SSD.


First cut at this (deeply technical):

1. Starting from highest address available and counting down,
   the data at the higher locations are all just pointers
   pointing at data in the rest of the SSD which are
   stored at address beginning at the 0 end.

   Call this the root pointer table.

   Note 1, 2


2. Pointer data grow from one end, the data itself grows from the other
   end.

3. No need to format the drive with this scheme!!!!!!!

4. Perfect for the embedded world because there is no code overheads
   associated with formatting.
   Put a new SSD in, the drive can be used immediately
   without having to format it! Perfect for TVs with PVRs, to Linux
   desktop OSes.

5. Each pointer points to arbitrary lengths of data and is free
   of context.
   That creates a problem because each device now doesn't know what
   data to expect when it opens the pointer table and tries to
   read the data that each pointer points at.

   The best way out of this is to agree on what the first 4 bytes in
   a structure pointed to by pointers from root table
   will hold. It should be unique number to indicate specific types
   of data.

   Note 3, 4.

6. Database operations become infinitely easy and orders of magnitude
   faster for desktops, mainframes and embedded devices.
  
   The reason is that each root pointer points to data that identifies
   itself without needing a filename.

   A database program can create thousands of data types and sift through
   the root table to find all its data without reference to a single file
   name.

   Note 3b.

7. A large part of file management operations can be dropped
   for faster database, gaming and embedded applications, because
   the file names and their management is modular and easy to drop
   when not needed.

   Note 3c.

8. Parallel operations by multiple CPUs to manage different
   data structures independently of each other across multiple
   SSDs.

   A small CPU could be managing the root pointer table, file management
   tables and cache management
   on a separate battery backed RAM and write back to the SSD
   only when it needs to.

   This means the file management, doesn't interfere with caching.
   The caching could be much smarter because it is software controlled.

etc.

Note 1
   The pointer with value 0 means its a null pointer
   while a pointer with all bits set to 1 means its the pointer
   list terminator. Because 0 is null pointer, sector 0 is
   is not used for standard data.

Note 2
   The root pointer table begins at the last page, but it may be
   a broken/worn out sector. To detect this, the first 4 bytes are not used
   and contain a unique improbable number. A check sum of this is number
   in the last 4 bytes of that sector. These 8 bytes must work out for the
   data in that sector to be read by operating system and treated as valid.
   Otherwise operating system moves on to the last but 1 sector to
   seek a valid sector for the beginning of the root pointer table.

Note 3
   The first 4 bytes in
   a structure pointed to by pointers from root table gives that
   data a implied data structure.

   For example, the value 1 could mean the rest of the data
   in that block are pointers to bad sectors that should not be used.
      
   Value 2 could be used to point to a data structure that gives
   filenames to data structures pointed to by the root table.
   Each entry points to a string that is a filename. If the pointer
   is 0, then no filename exists for that object. For each
   entry in the root pointer table, there is a corresponding entry
   in the filename table with same offset.
   #
   The separation of file objects from file names is
   perfect for minimalist embedded systems, as they can
   use the objects pointed to root table directly without having to maintain
   filename overheads in many an environment!!

   Value 3 could be used to mean a unix style text file.

   Value 4 could be used to mean database data objects with another 4 bytes
   to follow that indicates specific data type such as address, stock code,
   name, etc.

   Some open source authority will have to issue the numbers on
   a reasonable and free basis to avoid collisions.

Note 3b
   Value 5 could be used mean a collection of pointers of
   database data objects. These are copies of pointers
   taken from root table.
   It effectively collects randomly scattered data objects to make
   a complete database.
   #
   For embedded this is great because they can now manipulate
   database objects without file and filename management!
   No MMU.
   It is many orders of magnitude faster for desktops and mainframes
   to use this method because root pointer operations are atomic.
   You could build a transaction, and switch a pointer at
   the last minute to complete the transaction.

Note 3c
   Value 6 could be used to mean file permissions, dates, file size etc.
   This is useful for standard file management. Again this feature
   can be dropped in embedded where it may not be needed.
  
Note 4
   To prevent running out of numbers, the 4 bytes can be optionally
   be extended to 8 bytes. The switch over happens when the MSB of the
   4 byte number is set to 1 to indicate an 8 byte number.



There are many more advantages to not using a formatted drives
for Linux. But I guess it has to begin somewhere, and I'm thinking
the pressure to abandon formatting drives will begin when SSDs
without formatting coupled to smaller embedded devices begin to
eat into the performance of desktops with drives that have
formatted disks.

Well done to Mr. Marti Van Lin for sticking his neck out into the
proverbial jaws of a crocodile to check if the teeth are sharp.

And well done to Mr. Homer for being so 100% correct.

Already been done. It's effectively what happens when someone "formats" a
drive. The data-block bitmaps and inode-bitmaps are initialized and then
used to indicate what sections of disk (or RAM in this case) are available
and which are not.

abuse@eternal-september.org


Meet Ezekiel - Burson-Marselar troll trolling Linux
newsgroups.


Just because appil and micoshaft are loosing business to Linux,
thats not a good reason for Burson-Marstelar employees to be
trolling Linux newsgroups on their behalf.

abuse@eternal-september.org


Meet Ezekiel - Burson-Marselar troll trolling Linux
newsgroups.


Just because appil and micoshaft are loosing business to Linux,
thats not a good reason for Burson-Marstelar employees to be
trolling Linux newsgroups on their behalf.

What time does a "pretend software engineer" like you go to work at Quickie
Mart today?

Does your cash register run Linux?  Why do you look like a donkey?

Presumably you do, and on that basis you should be the best placed to
answer the second part of the question...?

Chris