WM5 Memory Map [Archive] - xda-developers

sawyer_family

11th January 2007, 02:38 PM

Hi guys (and gals)

First, thanks to c_shekhar for the Himalaya WM5 roms. Top Job

I'm quite new to WM5 and it has taken a little while for me to work out
how the XDA memory usage has changed from older PocketPC versions.
I thought I'd share how I think it looks for others, like me, who are using WM5
for the first time, thanks to the great ROMS on this site.
I've probably got bits of this wrong. Feel free to correct me

1st we need to understand what memory is in an XDAII:

128MB RAM (non-volatile after soft reset | volatile after hard reset)
32MB Flash ROM - Integrated with CPU (non-volatile after soft or hard reset)
32MB Flash ROM - Disk On Chip (DOC) (non-volatile after soft or hard reset) *

* All or part of this will get formatted if you select YES on the FORMAT STORAGE option on hard reset on WM5

The 32MB DOC Flash Rom is divided into two 16MB partitions by default:
Half goes to extROM
Half goes to persistant storage

Pre WM5 the memory map looked like this:

PRE WM5 - MEMORY MAP
--------------------------------------------------------------------------

...................| Storage (Installed Program Files, My Docs etc
128MB RAM.| Programs (running apps)
...................| Pocket PC OS (i.e. running state)

--------------------------------------------------------------------------

32MB Flash / CPU..| System ROM (i.e. where the ROM .nbf goes) (/Windows folder?)

--------------------------------------------------------------------------

16MB Flash DOC.| extROM (hidden by default. Contains vendor specific apps / hard reset - system startup)
16MB Flash DOC.| Persistant Storage (/Storage folder on pre WM5)

--------------------------------------------------------------------------

Pre WM5 pocketPC versions allowed you to dynamically select the amount
of (non-persistant) storage / Program space via the memory applet. Obviously
a hard reset would lose any programs installed into this RAM area of memory. Also the file system had a /Storage folder so you knew where to put impotant files that a hard reset wouldn't wipe out.

Things have all changed with WM5. Thus: (Based on c_shekhar 3.50a ROM)

WM5 - MEMORY MAP
--------------------------------------------------------------------------

...................| 37MB Programs (running apps)
...................| 40MB RAMDisk Storage (Non persistant storage /RAMdisk folder)
128MB RAM.| 24MB PagePool (PocketPC OS Cache ares (?))
...................| 27MB Pocket PC OS (i.e. running state)

--------------------------------------------------------------------------

32MB Flash / CPU | System ROM (i.e. where the ROM .nbf goes) (/Windows folder?)

--------------------------------------------------------------------------

16MB Flash DOC.| extROM (hidden by default. Contains vendor specific apps / hard reset - system startup)
16MB Flash DOC.| Persistant Storage (14MB Formatted space)**

--------------------------------------------------------------------------

** WM5 no longer has a /Storage folder. Now /My Document /Program Files etc
reside in this persistant area

Obviously one benefit to this re-arrangement is that a hard reset does not wipe
out your installed program, assuming you don't FORMAT STORAGE in the WM5 hard reset screen.

If you are using c_shekhar's ROM then the extROM area is not used. In fact its
probably is sitting there invisible to you with the old pre WM5 vendor apps wasting space. There are tools to make this 16MB partition visible and merge it into the existing 16MB DOC partition to give you 32MB of persistant storage.

Instructions >here (http://buzzdev.net/index.php?option=com_phorum&Itemid=125&phorum_query=read,26,6657,page=1)<

To check how much storage space you have:
Start>>Settings>>System Tab>>Memory

Storage Total will be circa 14.60MB for standard Install
Storage Total will be circa 30.53MB for merged extROM modification

There are also ways to change the size of the PagePool and RAMdisk but they are not discussed here. Search for c_shekhar + PagePool + RAMdisk

I hope this has been helpful

Please post any corrections, or further useful info

Regards

S_F

xmaxx

12th January 2007, 05:43 AM

Hi guys (and gals)

I hope this has been helpful

Please post any corrections, or further useful info

Regards

S_F

very helpful indeed
thanks for all the research

selangkahlagi

12th January 2007, 11:22 AM

sawyer_family

12th January 2007, 01:00 PM

Sorry to ask you silly questions...:) I am a newbie about PDA. And I stil didn't understand clearly concerning why extROM exist in PDA.

1. What is the real function extROM ?
2. I read from your writing, If I used c_shekhar rom it means extROM doesn't have any function anymore. Is it true ?
3. What are the risks if I merge extROM to storage ?

I hope you would like to be kind to explained this for me.

Regards
Selangkahlagi

...again I could be wrong here, and c_shekhar would know more about his ROM, but I think the general idea was:

1. XDA Manufacturer (i.e. HTC) provides main system ROM i.e. the pocketpc OS
2. The network supplier, or distributer (e.g. O2) provide the extROM ROM

Then when you hard boot the OS loads and autoruns and installs the branded
applications from the extROM to give you a clean branded install after a hard boot.

The extROM is readonly and invisible so you don't mess it up and can always
get back to the standard installation O2 or other supplier provided in the box.
My understanding is it is only used during a hard boot to install branded apps.

If you decide to install a ROM like c_shekhar's then he installs all the software
you need into the main system ROM. He doesn't use extROM to provide any
other applications that would install on a hard boot. In fact I assume he
takes out any call to the autorun in extROM which is why there are no app loads
when you hard boot his ROMs.

So you have a choice. Leave extROM alone and let 16MB of nonvolatile flash
rom sit there with O2 apps you'll probably never use again. Or, merge it into
the 16MB of storage space and get circa 32mb or storage.

There are always risks from flashing a pda device and messing about with flash
memory, especially from a non-official source. But then there are huge benefits from
c_shekhar providing us with a fantastic WM5 ROM that we otherwise wouldn't
have.

Hope this is correct and helpful.

S_F

creations_31

12th January 2007, 03:13 PM

sawyer_family

12th January 2007, 06:01 PM

Dear all ,After upgarding rom of Shekhar My device stopped Reading MMC And SD card,unfortunately till now i have not get any reply about this issue ,can some one help me outof it ?

Require help >>>>>>>>

Thanks In advance.

Wrong thread to be asking in. But SD slot works ok on my XDA with 3.50a.40CS

I'd suggest you go back to an official ROM version and verify its not a hardware fault.

c_shekhar

12th January 2007, 06:30 PM

...again I could be wrong here, and c_shekhar would know more about his ROM, but I think the general idea was:

1. XDA Manufacturer (i.e. HTC) provides main system ROM i.e. the pocketpc OS
2. The network supplier, or distributer (e.g. O2) provide the extROM ROM

Then when you hard boot the OS loads and autoruns and installs the branded
applications from the extROM to give you a clean branded install after a hard boot.

The extROM is readonly and invisible so you don't mess it up and can always
get back to the standard installation O2 or other supplier provided in the box.
My understanding is it is only used during a hard boot to install branded apps.

If you decide to install a ROM like c_shekhar's then he installs all the software
you need into the main system ROM. He doesn't use extROM to provide any
other applications that would install on a hard boot. In fact I assume he
takes out any call to the autorun in extROM which is why there are no app loads
when you hard boot his ROMs.

So you have a choice. Leave extROM alone and let 16MB of nonvolatile flash
rom sit there with O2 apps you'll probably never use again. Or, merge it into
the 16MB of storage space and get circa 32mb or storage.

There are always risks from flashing a pda device and messing about with flash
memory, especially from a non-official source. But then there are huge benefits from
c_shekhar providing us with a fantastic WM5 ROM that we otherwise wouldn't
have.

Hope this is correct and helpful.

S_F

Good Sutdy and informations for the newbees. appriciations for sawyer_family. There exists the autorun program for installing the third party S/Ws and configurations at the time of hard reset developed by buzz. But, I have not provided it in the ROM. It can install the S/Ws and configurations from the resrve space into the RAM just like it used to be with the ExtROM. Here the advantage is that ExtROM can be placed on the Storage card. Like I am using it on my device to install the third party S/Ws and all the stuff at the time of hard reset. I have placed all these stuff in folder called "Storage Card/ExtROM". May be I provide it in my next release If people require. ......

selangkahlagi

12th January 2007, 07:08 PM

Good Sutdy and informations for the newbees. appriciations for sawyer_family. There exists the autorun program for installing the third party S/Ws and configurations at the time of hard reset developed by buzz. But, I have not provided it in the ROM. It can install the S/Ws and configurations from the resrve space into the RAM just like it used to be with the ExtROM. Here the advantage is that ExtROM can be placed on the Storage card. Like I am using it on my device to install the third party S/Ws and all the stuff at the time of hard reset. I have placed all these stuff in folder called "Storage Card/ExtROM". May be I provide it in my next release If people require. ......

Nice idea c_shekhar, it is a brillian idea to put extROM in storage card. It will safe much place in ROM. I will waiting your work mate !!!!

selangkahlagi

12th January 2007, 07:13 PM

...again I could be wrong here, and c_shekhar would know more about his ROM, but I think the general idea was:

1. XDA Manufacturer (i.e. HTC) provides main system ROM i.e. the pocketpc OS
2. The network supplier, or distributer (e.g. O2) provide the extROM ROM

Then when you hard boot the OS loads and autoruns and installs the branded
applications from the extROM to give you a clean branded install after a hard boot.

The extROM is readonly and invisible so you don't mess it up and can always
get back to the standard installation O2 or other supplier provided in the box.
My understanding is it is only used during a hard boot to install branded apps.

If you decide to install a ROM like c_shekhar's then he installs all the software
you need into the main system ROM. He doesn't use extROM to provide any
other applications that would install on a hard boot. In fact I assume he
takes out any call to the autorun in extROM which is why there are no app loads
when you hard boot his ROMs.

So you have a choice. Leave extROM alone and let 16MB of nonvolatile flash
rom sit there with O2 apps you'll probably never use again. Or, merge it into
the 16MB of storage space and get circa 32mb or storage.

There are always risks from flashing a pda device and messing about with flash
memory, especially from a non-official source. But then there are huge benefits from
c_shekhar providing us with a fantastic WM5 ROM that we otherwise wouldn't
have.

Hope this is correct and helpful.

S_F

Thany you sawyer_family, you help me much to understand this topic. :)