> Hi there, > > It seems like the bios of this machine doesn't have any type of > configuration regarding the memory mapping. > I'm already using the kernel-hugemem , but the problem remains. > What else can be done? > > By the way, if the machine had more than one cpu, the problem would remain? > > Best regards, > Bruno Sousa > > -----Mensagem original----- > De: centos-bounces at centos.org [mailto:centos-bounces at centos.org] Em nome de > James Pearson > Enviada: quinta-feira, 22 de Junho de 2006 15:54 > Para: CentOS mailing list > Assunto: Re: [CentOS] x86 uniprocessor 4GB memory > > Bruno Sousa wrote: > >>Hi there, >> >>I'm currently using CentOS 4.3 (Server edition) in a HP DC 5100 with the >>IntelR 915GV chipset, powered by a PIV 3.0GHZ. >> >>Now I'm facing a problem, with memory. >> >>I got myself 4GB of memory, the system bios detects it correctly, but in >>Linux can only see around 3.5gb memory. With the default kernel-smp (I use >>hyperthread) or with kernel-hugemem , I have the same results. >> >>Is there any way to workaround this issue? > > > It is probably the 4Gb memory hole issue - various 'things' reserve > memory below 4GB so hiding the real memory from the OS. > > Your BIOS may have a mapping option to map some of this hidden real > memory to above 4Gb - however, you need to use a hugemem kernel to > access this memory. Having multiple CPUs would make no difference. The hugemem kernel would only see this memory if the BIOS could map it to above 4Gb - if the BIOS can't, then there is nothing above 4Gb for the hugemem kernel to see. A newer version of the BIOS _might_ have added this support ... James Pearson