memory allocation on DM 7000s

[francior]

Hello everybody,

i´m new on this forum (congratulations for this top forum) and newbie on Dreambox world. For a couple of weeks i've received my second hand DM 7000s and up to day i'm very happy with it. Now a doubt:

On linux command line and top command i see that the total memory is 29,2 MB. What i know, the DM 7000 comes with 64 MB buit in. Then i would like to know how is the memory allocation on startup and why the linux command line says me that i have only 29,2 total memory. How is the rest allocated ?.

Regards.

 

[rolfw]

Not sure about the allocation, but the first thing I did with mine, was to add a USB stick, I then transferred the var directory onto it. This means that you are not faced with no space error messages when loading plugins.

 

[francior]

Thank you rolfw for replaying. I will do it too (USB stick or compact flash) but as newbie on Drembox i want to know everything about it. I suspect that at startup all software is loaded on RAM memory (for that reason i have only 29,2 free memory) but i would like only to confirm that. Another doubt, what do you think about to use compact flash instead of USB stick ?.

Regards.

 

[rolfw]

I guess that you can use either, but USB sticks seem to perform better and seem to be the most common option.

 

[wallycharlo]

the top command will show you the total amount of memory you have,along with other features such as how much is actually being used at that time.this refers to RAM (random access memory) which is volatile : ie,once you remove the power you lose all data.

From what you describe,you have 32MB of RAM and not 64.

The operating system (ie the image you are using) is stored in flash memory.this memory is non-volatile,so the data is retained once the power is removed.if this was not the case then you would need to reflash your box every time the power has been removed.as soon as you boot up your box,the operating system is copied from the flash memory into the RAM.RAM memory is very fast,and can be accessed very quicly when compared to slower flash memory.flash also needs high voltages to write to the memory,whereas RAM can operate at much lower voltages.

adding a USB stick will expand the flash memory ... so it will give you the possibility of having more cams,plugins,etc.but,it wont really enable you to run applications quicker as the amount of RAM (which is where the programs run) is still fixed.while running,your DB will constantly swap data back and forth between virtual memory (USB/hdd) and the RAM ...

in general, you can execute the command "df" in telnet,this will show you all the memory allocations

 

[francior]

wallycharlo, i´ve read on german forums that 32 MB are ready for operating system (user memory) and 32 MB for internal system management (system memory). On model 7020, 96 MB built in memory, 64 MB for operating system and 32 MB for internal system management.

Following data of my box:

1. top

Mem: 23636K used, 6408K free, 0K shrd, 748K buff, 5872K cached
Load average: 1.00, 1.00, 1.00 (State: S=sleeping R=running, W=waiting)

2. df -k

~ > df -k
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/root 4096 4096 0 100% /
/dev/mtdblock/1 1792 1368 424 76% /var
/dev/ide/host0/bus0/target0/lun0/part1156259060 41868 156217192 0% /hdd

On previous data (top command) if we add all values:

23636K used + 6408K free + 0K shrd + 748K buff + 5872K cached = 36664k (35.8 M we have the total memory for operating system.

Then as you say, the operating system is copied to RAM memory :

36664k - 4096k (/dev/root) - 1792k (/dev/mtdblock/1) = 30776k (30,05 M

Then i can now understand why the info memory menu says that the total memory is 29,2 MB (up to 30,05 MB are aproximately 800k on running processes).

Anyway thank you all for your support.

Regards.