[PATCH] Update to Documentation/ramdisk.txt - take 2

[PATCH] Update to Documentation/ramdisk.txt - take 2

[Jim Nelson]

@#%*^#$ Mozilla.  Line wrap was set too low.

Let's try this again - hopefully, Mozilla won't mangle my patch this time.

Jim


Description: General cleanup and update to ramdisk documentation, removing 
incorrect and obsolete information.  Apply against 2.6.9.

Signed-off-by: James Nelson <james4765@gmail.com>

diff -urN linux-2.6.9-original/Documentation/ramdisk.txt 
linux-2.6.9/Documentation/ramdisk.txt
--- linux-2.6.9-original/Documentation/ramdisk.txt      2004-08-14 
01:36:13.000000000 -0400
+++ linux-2.6.9/Documentation/ramdisk.txt       2004-10-22 19:18:06.808819898 -0400
@@ -5,115 +5,66 @@

         1) Overview
         2) Kernel Command Line Parameters
-       3) Using "rdev -r" With New Kernels
+       3) Using "rdev -r"
         4) An Example of Creating a Compressed RAM Disk


  1) Overview
  -----------

-As of kernel v1.3.48, the RAM disk driver was substantially changed.
-
-The older versions would grab a chunk of memory off the top before
-handing the remainder to the kernel at boot time. Thus a size parameter
-had to be specified via "ramdisk=1440" or "rdev -r /dev/fd0 1440" so
-that the driver knew how much memory to grab.
-
-Now the RAM disk dynamically grows as more space is required. It does
-this by using RAM from the buffer cache. The driver marks the buffers
-it is using with a new "BH_Protected" flag so that the kernel does
-not try to reuse them later. This means that the old size parameter
-is no longer used, new command line parameters exist, and the behavior
-of the "rdev -r" or "ramsize" (usually a symbolic link to "rdev")
-command has changed.
-
-Also, the new RAM disk supports up to 16 RAM disks out of the box, and can
-be reconfigured in rd.c to support up to 255 RAM disks.  To use multiple
-RAM disk support with your system, run 'mknod /dev/ramX b 1 X' and chmod
-(to change its permissions) it to your liking.  The default /dev/ram(disk)
-uses minor #1, so start with ram2 and go from there.
-
-The old "ramdisk=<ram_size>" has been changed to "ramdisk_size=<ram_size>"
-to make it clearer.  The original "ramdisk=<ram_size>" has been kept around
-for compatibility reasons, but it will probably be removed in 2.1.x.
+The RAM disk driver is a way to use main system memory as a block device.  It
+is required for initrd, an initial filesystem used if you need to load modules
+in order to access the root filesystem (see Documentation/initrd.txt).  It can
+also be used for a temporary filesystem for crypto work, since the contents
+are erased on reboot.
+
+The RAM disk dynamically grows as more space is required. It does this by using
+RAM from the buffer cache. The driver marks the buffers it is using as dirty
+so that the VM subsystem does not try to reclaim them later.
+
+Also, the RAM disk supports up to 16 RAM disks out of the box, and can
+be reconfigured to support up to 255 RAM disks - change "#define NUM_RAMDISKS"
+in drivers/block/rd.c.  To use RAM disk support with your system, run
+'./MAKEDEV ram' from the /dev directory.  RAM disks are all major number 1, and
+start with minor number 0 for /dev/ram0, etc.  If used, modern kernels use
+/dev/ram0 for an initrd.
+
+The old "ramdisk=<ram_size>" has been changed to "ramdisk_size=<ram_size>" to
+make it clearer.  The original "ramdisk=<ram_size>" has been kept around for
+compatibility reasons, but it may be removed in the future.

  The new RAM disk also has the ability to load compressed RAM disk images,
  allowing one to squeeze more programs onto an average installation or
  rescue floppy disk.

-Notes: You may have "/dev/ram" or "/dev/ramdisk" or both. They are
-equivalent from the standpoint of this document. Also, the new RAM disk
-is a config option. When running "make config", make sure you enable
-RAM disk support for the kernel with which you intend to use the RAM disk.
-

  2) Kernel Command Line Parameters
  ---------------------------------

-       ramdisk_start=NNN
-       =================
-
-To allow a kernel image to reside on a floppy disk along with a compressed
-RAM disk image, the "ramdisk_start=<offset>" command was added. The kernel
-can't be included into the compressed RAM disk filesystem image, because
-it needs to be stored starting at block zero so that the BIOS can load the
-boot sector and then the kernel can bootstrap itself to get going.
-
-Note: If you are using an uncompressed RAM disk image, then the kernel can
-be a part of the filesystem image that is being loaded into the RAM disk,
-and the floppy can be booted with LILO, or the two can be separate as
-is done for the compressed images.
-
-If you are using a two-disk boot/root setup (kernel on #1, RAM disk image
-on #2) then the RAM disk would start at block zero, and an offset of
-zero would be used. Since this is the default value, you would not need
-to actually use the command at all.
-
-If instead, you have a "zImage" of about 350 kB, and a "fs_image.gz" of
-say about 1 MB, and you want them both on the same disk, then you
-would use an offset. If you stored the "fs_image.gz" onto the floppy
-starting at an offset of 400 kB, you would use "ramdisk_start=400".
-
-
-       load_ramdisk=N
-       ==============
-
-This parameter tells the kernel whether it is to try to load a
-RAM disk image or not. Specifying "load_ramdisk=1" will tell the
-kernel to load a floppy into the RAM disk. The default value is
-zero, meaning that the kernel should not try to load a RAM disk.
-
-
-       prompt_ramdisk=N
-       ================
-
-This parameter tells the kernel whether or not to give you a prompt
-asking you to insert the floppy containing the RAM disk image. In
-a single floppy configuration the RAM disk image is on the same floppy
-as the kernel that just finished loading/booting and so a prompt
-is not needed. In this case one can use "prompt_ramdisk=0". In a
-two floppy configuration, you will need the chance to switch disks,
-and thus "prompt_ramdisk=1" can be used. Since this is the default
-value, it doesn't really need to be specified.
-
         ramdisk_size=N
         ==============

  This parameter tells the RAM disk driver to set up RAM disks of N k size.  The
-default is 4096 (4 MB).
+default is 4096 (4 MB), 8192 (8 MB) on S390.
+
+       ramdisk_blocksize=N
+       ===================
+
+This parameter tells the RAM disk driver how many bytes to use per block.  The
+default is 512.

-3) Using "rdev -r" With New Kernels
------------------------------------

-The usage of the word (two bytes) that "rdev -r" sets in the kernel image
-has changed. The low 11 bits (0 -> 10) specify an offset (in 1 k blocks)
-of up to 2 MB (211) of where to find the RAM disk (this used to be the
-size). Bit 14 indicates that a RAM disk is to be loaded, and bit 15
-indicates whether a prompt/wait sequence is to be given before trying
-to read the RAM disk. Since the RAM disk dynamically grows as data is
-being written into it, a size field is no longer required. Bits 11
-to 13 are not currently used and may as well be zero. These numbers
-are no magical secrets, as seen below:
+3) Using "rdev -r"
+------------------
+
+The usage of the word (two bytes) that "rdev -r" sets in the kernel image is
+as follows. The low 11 bits (0 -> 10) specify an offset (in 1 k blocks) of up
+to 2 MB (211) of where to find the RAM disk (this used to be the size). Bit
+14 indicates that a RAM disk is to be loaded, and bit 15 indicates whether a
+prompt/wait sequence is to be given before trying to read the RAM disk. Since
+the RAM disk dynamically grows as data is being written into it, a size field
+is not required. Bits 11 to 13 are not currently used and may as well be zero.
+These numbers are no magical secrets, as seen below:

  ./arch/i386/kernel/setup.c:#define RAMDISK_IMAGE_START_MASK     0x07FF
  ./arch/i386/kernel/setup.c:#define RAMDISK_PROMPT_FLAG          0x8000
@@ -152,10 +103,10 @@
  To create a RAM disk image, you will need a spare block device to
  construct it on. This can be the RAM disk device itself, or an
  unused disk partition (such as an unmounted swap partition). For this
-example, we will use the RAM disk device, "/dev/ram".
+example, we will use the RAM disk device, "/dev/ram0".

  Note: This technique should not be done on a machine with less than 8 MB
-of RAM. If using a spare disk partition instead of /dev/ram, then this
+of RAM. If using a spare disk partition instead of /dev/ram0, then this
  restriction does not apply.

  a) Decide on the RAM disk size that you want. Say 2 MB for this example.
@@ -164,11 +115,11 @@
     area (esp. for disks) so that maximal compression is achieved for
     the unused blocks of the image that you are about to create.

-       dd if=/dev/zero of=/dev/ram bs=1k count=2048
+       dd if=/dev/zero of=/dev/ram0 bs=1k count=2048

  b) Make a filesystem on it. Say ext2fs for this example.

-       mke2fs -vm0 /dev/ram 2048
+       mke2fs -vm0 /dev/ram0 2048

  c) Mount it, copy the files you want to it (eg: /etc/* /dev/* ...)
     and unmount it again.
@@ -177,7 +128,7 @@
     will be approximately 50% of the space used by the files. Unused
     space on the RAM disk will compress to almost nothing.

-       dd if=/dev/ram bs=1k count=2048 | gzip -v9 > /tmp/ram_image.gz
+       dd if=/dev/ram0 bs=1k count=2048 | gzip -v9 > /tmp/ram_image.gz

  e) Put the kernel onto the floppy

@@ -203,4 +154,14 @@
  users may wish to combine steps (d) and (f) by using a pipe.

  --------------------------------------------------------------------------
-                                               Paul Gortmaker 12/95
+                                               Paul Gortmaker 12/95
+
+Changelog:
+----------
+
+10-22-04 :     Updated to reflect changes in command line options,
+               remove obsolete references, general cleanup.
+               James Nelson (james4765@gmail.com)
+
+
+12-95 :                Original Document

Re: [PATCH] Update to Documentation/ramdisk.txt - take 2

[Kurt Wall]

On Fri, Oct 22, 2004 at 09:45:13PM -0400, Jim Nelson took 229 lines to write:
> @#%*^#$ Mozilla.  Line wrap was set too low.
> 
> Let's try this again - hopefully, Mozilla won't mangle my patch this time.

Urgl:

patching file Documentation/ramdisk.txt
Hunk #1 FAILED at 5.
Hunk #2 FAILED at 103.
Hunk #3 FAILED at 115.
Hunk #4 FAILED at 128.
Hunk #5 FAILED at 154.
5 out of 5 hunks FAILED -- saving rejects to file
Documentation/ramdisk.txt.rej

Kurt
-- 
Next to being shot at and missed, nothing is really quite as satisfying
as an income tax refund.
	-- F. J. Raymond

Re: [PATCH] Update to Documentation/ramdisk.txt - take 2

[Lee Revell]

On Fri, 2004-10-22 at 22:12 -0400, Kurt Wall wrote:
> On Fri, Oct 22, 2004 at 09:45:13PM -0400, Jim Nelson took 229 lines to write:
> > @#%*^#$ Mozilla.  Line wrap was set too low.
> > 
> > Let's try this again - hopefully, Mozilla won't mangle my patch this time.
> 
> Urgl:
> 
> patching file Documentation/ramdisk.txt
> Hunk #1 FAILED at 5.

You cannot just increase the line wrap and hope Mozilla will do the
right thing.  Mozilla should have an option to insert preformatted text.

If there is no such option please report it as a bug.

Lee

mozilla-mail damage [was Re: [PATCH] Update to Documentation/ramdisk.txt - take 2]

[Lee Revell]

On Fri, 2004-10-22 at 22:35 -0400, Lee Revell wrote:
> On Fri, 2004-10-22 at 22:12 -0400, Kurt Wall wrote:
> > On Fri, Oct 22, 2004 at 09:45:13PM -0400, Jim Nelson took 229 lines to write:
> > > @#%*^#$ Mozilla.  Line wrap was set too low.
> > > 
> > > Let's try this again - hopefully, Mozilla won't mangle my patch this time.
> > 
> > Urgl:
> > 
> > patching file Documentation/ramdisk.txt
> > Hunk #1 FAILED at 5.
> 
> You cannot just increase the line wrap and hope Mozilla will do the
> right thing.  Mozilla should have an option to insert preformatted text.

OK I just went and installed mozilla mail to see what the problem is and
it's worse than I thought.

The problem is that Mozilla does not grok the standard X clipboard at
all.

Try these tests:

1. Highlight some text in an xterm.  Paste with middle button into
Mozlla  mail window.  Then paste with the middle button into vim.  Both
work BUT the patch is whitespace damaged.

2. Run diff foo bar | xclip.  Paste with middle button into Mozilla.
Nothing.  Then paste with middle button into vim.  Works.

#2 would not mangle the patch IF it worked which it doesn't.  Mozilla
does not have a setting to insert a text file.  So many people just do
#1.

No wonder people are mangling patches, the Mozilla mail client is very
broken.  PLEASE, file bug reports!

Lee


	

Re: mozilla-mail damage [was Re: [PATCH] Update to Documentation/ramdisk.txt - take 2]

[Jim Nelson]

Lee Revell wrote:
> On Fri, 2004-10-22 at 22:35 -0400, Lee Revell wrote:
> 
>>On Fri, 2004-10-22 at 22:12 -0400, Kurt Wall wrote:
>>
>>>On Fri, Oct 22, 2004 at 09:45:13PM -0400, Jim Nelson took 229 lines to write:
>>>
>>>>@#%*^#$ Mozilla.  Line wrap was set too low.
>>>>
>>>>Let's try this again - hopefully, Mozilla won't mangle my patch this time.
>>>
>>>Urgl:
>>>
>>>patching file Documentation/ramdisk.txt
>>>Hunk #1 FAILED at 5.
>>
>>You cannot just increase the line wrap and hope Mozilla will do the
>>right thing.  Mozilla should have an option to insert preformatted text.
> 
> 
> OK I just went and installed mozilla mail to see what the problem is and
> it's worse than I thought.
> 
> The problem is that Mozilla does not grok the standard X clipboard at
> all.
> 
> Try these tests:
> 
> 1. Highlight some text in an xterm.  Paste with middle button into
> Mozlla  mail window.  Then paste with the middle button into vim.  Both
> work BUT the patch is whitespace damaged.
> 
> 2. Run diff foo bar | xclip.  Paste with middle button into Mozilla.
> Nothing.  Then paste with middle button into vim.  Works.
> 
> #2 would not mangle the patch IF it worked which it doesn't.  Mozilla
> does not have a setting to insert a text file.  So many people just do
> #1.
> 
> No wonder people are mangling patches, the Mozilla mail client is very
> broken.  PLEASE, file bug reports!
> 
> Lee
> 
>

Probably need to make using Paul Jackson's sendpatchset script de riguer 
recommendation for GUI mail client users for right now, until this issue is hashed 
out one way or another.

However, sendpatchset doesn't work with SMTP authentication, which my ISP uses, 
and I'm too tired to get sendmail working on one of my machines tonight.  Maybe 
sometime tomorrow.

Re: mozilla-mail damage [was Re: [PATCH] Update to Documentation/ramdisk.txt - take 2]

[Lee Revell]

On Sat, 2004-10-23 at 00:18 -0400, Jim Nelson wrote:
> Probably need to make using Paul Jackson's sendpatchset script de riguer 
> recommendation for GUI mail client users

Nope, just Mozilla.  Evolution does the Right Thing - it handles the X
clipboard correctly AND has a menu item to "insert text file".

Lee

Re: mozilla-mail damage [was Re: [PATCH] Update to Documentation/ramdisk.txt - take 2]

[Con Kolivas]

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Lee Revell wrote:
> On Sat, 2004-10-23 at 00:18 -0400, Jim Nelson wrote:
> 
>>Probably need to make using Paul Jackson's sendpatchset script de riguer 
>>recommendation for GUI mail client users
> 
> 
> Nope, just Mozilla.  Evolution does the Right Thing - it handles the X
> clipboard correctly AND has a menu item to "insert text file".

For what it's worth, thunderbird attaches patches beautifully inlined by 
default. No need to cut and paste.

Con

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Re: mozilla-mail damage [was Re: [PATCH] Update to Documentation/ramdisk.txt - take 2]

[Paul Jackson]

> However, sendpatchset doesn't work with SMTP authentication, which my ISP uses, 

The underlying Python smtplib module has authentication support.

You could probably hack your private copy of sendpatchset by adding
something like the following line with hardcoded strings to call the
python smtp login() method with your ISP user id and password:


    try:
        s=smtplib.SMTP(smtpserver)
    except:
        print "%s: Oops - Cant connect to SMTP Server <%s>" % (cmd, smtpserver)
        sys.exit(1)

    s.set_debuglevel(0)
+   s.login("james4765@verizon.net", "my_not_so_secret_password")
    if not actually_send_message:


The above change is untested speculation - good luck.

A proper solution might involve adding an optional user login id string
to the sendpatchset control file entry for the SMTP server:

	SMTP: <smtp_server_ipaddr> [<authenticated_smtp_user_login_id>]

and if this extra field was present, interactively collecting the
password during use and making the above "s.login()" call.

You'd want to somehow avoid collecting the password more than once per
sendpatchset session.  Since the current code reconnects many times
to the smtp server (twice per patch. first to verify and then to
actually send the message), either rearrange the smtp connection
handling in the current code to reuse a single connection, or collect
the password once and remember it in a python variable to use for each
reconnect during an entire sendpatchset session.

Since I don't happen to need this, I'm at little risk for adding this
anytime soon.  If someone else wants to send me a nice pretty solution,
I'd update my master copy if I found the solution to my liking.

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@sgi.com> 1.650.933.1373

Re: mozilla-mail damage [was Re: [PATCH] Update to Documentation/ramdisk.txt - take 2]

[David Ford]

[-- Attachment #1: Type: text/plain, Size: 491 bytes --]

just do one of:

1> drag into attachments window
2> paste as text and format plain
3> send as plain text email unwrapped

-david

Lee Revell wrote:

>On Sat, 2004-10-23 at 00:18 -0400, Jim Nelson wrote:
>  
>
>>Probably need to make using Paul Jackson's sendpatchset script de riguer 
>>recommendation for GUI mail client users
>>    
>>
>
>Nope, just Mozilla.  Evolution does the Right Thing - it handles the X
>clipboard correctly AND has a menu item to "insert text file".
>
>Lee
>
>  
>

[-- Attachment #2: david+challenge-response.vcf --]
[-- Type: text/x-vcard, Size: 183 bytes --]

begin:vcard
fn:David Ford
n:Ford;David
email;internet:david@blue-labs.org
title:Industrial Geek
tel;home:Ask please
tel;cell:(203) 650-3611
x-mozilla-html:TRUE
version:2.1
end:vcard

Re: mozilla-mail damage [was Re: [PATCH] Update to Documentation/ramdisk.txt - take 2]

[Lee Revell]

On Sat, 2004-10-23 at 15:56 -0400, David Ford wrote:
> just do one of:
> 
> 1> drag into attachments window

I don't want to attach it, I want it inline.  This is not intuitive.

> 2> paste as text and format plain

Not possible.  Mozilla does not grok the X clipboard.

> 3> send as plain text email unwrapped
> 

Um, how do I get it into the message body in the first place?

I am not saying it's impossible to send a non-mangled patch with
Mozilla.  But, it certainly is much harder than sending a mangled one.
This is a BUG.

Lee