Kernel selection for up to 64GB of system memory in LiveUSB PCLOS LXDE

[unist]

I am running a LiveUSB PCLOS LXDE 2012 that I chainload from my main install in Hard Disk Drive No 2, which is PCLOS KDE 2012. I have 8 GB physical RAM that my main install recognizes, once I changed its kernel to 2.6.38.8-pclos3.pae.bfs

I tried to do the same for my LiveUSB PCLOS LXDE and installed kernel-2.6.38.8-pclos1.pae.bfs, but after reboot I found that my reported physical RAM stayed the same, with the maximum 4 GB [Memory: 3373MB (444MB used)]

I repeated the procedure with same result for:

kernel-2.6.38.8-pclos3.pae.bfs

kernel-3.2.18-pclos2.pae.bfs

I used these kernels because in their respective properties it is stated: “It is optimised for i686 CPUs, supports up to 64GB of system memory (highmem enabled)”

Kernel reported for my system is: Linux 3.2.18-pclos2.bfs (i686)

This correspond to the original kernel for LiveUSB PCLOS LXDE 2012: kernel-3.2.18-pclos2.bfs

From its properties: “it is optimised for i686 CPUs, supports up to 4GB of system memory (highmem enabled)”

I have not tried kernels for AMD chipset, which is my case: 4x AMD FX(tm)-4100 Quad-Core Processor, family, model, stepping: 21, 1, 2 (AMD Opteron/Athlon64/FX).

From kernel-3.2.18-pclos2.a64, in its properties: “This kernel package contains a AMD64/Opteron (K8) optimised Linux 3.2.18-pclos2.a64 kernel compiled for the x86 arch”. Similar statement is included for others kernels for AMD. In all these cases maximum RAM is limited to 4 GB. For this reason I have not tried these kernels.

Is it possible to change the kernel for LiveUSB PCLOS LXDE in order to make the system recognize more than 4 GB?

[scoundrel]

live usb is just that.. anything you install will be lost on the next reboot.. might want to try booting with persistence or do a remaster with the chosen kernel then use that live usb 

[unist]

live usb is just that.. anything you install will be lost on the next reboot.. might want to try booting with persistence or do a remaster with the chosen kernel then use that live usb 

scoundrel, thank you for your post. I already set my LiveUSB to boot by default with persistence. My intents to change kernel were in this mode. I read the kernel article in the PCLOS Knowledge Base but did not find indications that may apply to LiveUSB with persistence, or that state that kernel change is not possible for it. If that were the case, it is fine for me. I just want to know if it is possible or not for a running system (without remaster).

[horusfalcon]

Question here that might be relevant:  Is it possible to install to USB in the same way that it is possible to install to and then boot from a USB hard drive? 

I use a portable USB hard drive at work as a diagnostic & recovery tool for my Ghost server (thankfully, I've never needed it to this point), and it works beautifully to drop the system to a well-working Linux when I need it.  It's persistent, and quite fast, actually.

Just a thought.

Later On,
D

[Just17]

live usb is just that.. anything you install will be lost on the next reboot.. might want to try booting with persistence or do a remaster with the chosen kernel then use that live usb 

scoundrel, thank you for your post. I already set my LiveUSB to boot by default with persistence. My intents to change kernel were in this mode. I read the kernel article in the PCLOS Knowledge Base but did not find indications that may apply to LiveUSB with persistence, or that state that kernel change is not possible for it. If that were the case, it is fine for me. I just want to know if it is possible or not for a running system (without remaster).

To change to a different kernel you need to change before you remaster.

[unist]

To change to a different kernel you need to change before you remaster.

Thank you for your indication. Now I am quite clear.

[unist]

Question here that might be relevant:  Is it possible to install to USB in the same way that it is possible to install to and then boot from a USB hard drive? 

Interesting question.....

[Just17]

Question here that might be relevant:  Is it possible to install to USB in the same way that it is possible to install to and then boot from a USB hard drive? 

Interesting question.....

Yes it is ......  just select the USB flash drive when installing.

Of course USB flash drives are not meant for constant access that a normally installed OS does, and so will be inclined to fail after a time.

[Grandpa]

@Just17 why did you say this "USB flash drives are not meant for constant access"?  I am not finding fault with the statement just wondering.

[pags]

@Just17 why did you say this "USB flash drives are not meant for constant access"?  I am not finding fault with the statement just wondering.

Because flash memory (the type used in USB drives) have a finite number of read/write cycles (usually around 100,000 for the more common types...newer, more expensive types are pushing 1,000,000 now).  The memory cells are grouped into (fairly) large aggregates of memory such that even if a single byte of data is changed, an entire cell (many kilobytes) of flash memory has to be deleted and re-written to accommodate it.  When there is other data in the same cell that needs to remain the same, this data needs to be written out to another (unused) cell so the cell being changed can be deleted in preparation of re-writing the data.  This incurs multiple read/write operations on multiple cells.

There is (usually) an on-board algorithm that attempts to spreads these operations across all the cells on the device (called "wear-leveling"), but the end result is if you're writing (and, presumably, deleting) data to a flash device, it has a finite life span.  For just "reading", there is almost no wear on the device, so it has a "near-infinite" life span as a read-only device (but then, what's the fun in that?).

Sorry to jump in on you, Just17...

 

[Just17]

@Just17 why did you say this "USB flash drives are not meant for constant access"?  I am not finding fault with the statement just wondering.

Flash drives have a limited number of writes before they are susceptible to failure.
This is not a limitation one finds on HDDs.

https://en.wikipedia.org/wiki/Flash_memory#Memory_wear


EDIT
          Thanks pags .....  was a bit slow responding 

[Grandpa]

Thanks guys.  I didn't know that.