Is there anyway to disable a region of RAM for use? - operating-system

Lately I have been experiencing general crashed as freezes, so I ran a MemTest86, which failed. Seems like there are a small portion of RAM that have faulty bits, which are likely the cause.
Is there some way to disable this region of memory either in BIOS or in the OS (Win10, currently)?

The firmware might technically support something to exclude faulty RAM; but if it does it's not working.
I don't think Windows supports anything to exclude faulty RAM.
Linux does supports this; if and only if the memory isn't used before the kernel sets up its memory management. The problem would be installing an OS when the installer will probably use the faulty memory.
If you can get Linux to work, then you can install Windows inside a virtual machine running on Linux. Of course then there's still no way to determine how long it's going to last before more RAM becomes faulty.
Mostly; the easiest and safest option is to replace the faulty RAM.

Related

Omnet++ on Windows or Linux?

I'm going to produce VoLTE packet stream on OMNET++. Which OS is recommended for installing OMNET++, Linux or Win?
My laptop system is win10. If Linux is better, is there any problem if I use linux on VBox?
Thanx for your kind recommendations.
Linux [1] is definitely the recommended OS for using OMNeT++.
In particular, you will have the best experience with Ubuntu 18.04.1 - if you're using the latest OMNeT++ release that is. Older versions might work better on earlier Ubuntu releases.
Running it in a virtual machine should not cause any issues.
The only case that might be problematic is using the 3D integration (OSG and osgEarth). Rendering performance might be worse (or it might not work at all), but this depends on your setup. There are a few GPU/driver/config/etc. combinations where even this works quite well.
EDIT:
The reason is that even though Windows is fully supported as well, it simply performs significantly worse - especially during building either OMNeT++, or any model libraries or projects. We suspect that it is caused mostly by how NTFS works, among a variety other things.
On top of that, certain "more exotic" features in some model libraries might only be available on Linux.
[1]: Well, technically it's GNU/Linux, or more appropriately, GNU+Linux. :D
I suggestion Linux (Example : Debian, Fedora) or Unix, Because Linux or Unix have most stable using develop OMNeT++ to working great.

Which operating system uses the lowest amount of system ressources?

I'm using a program that is calculating things as it receives information and I need it to be running on multiple virtual machines on my PC at the same time.
Now before I was going to set this up, I was wondering which operating system would be ideal to be running on the virtual machines to run as many of them as possible on restricted ressources? The only requirement is that my program is not able to run on Linux.
I was thinking of going back to Windows XP on each virtual machine, assuming the newer operating systems are taking too much ressources for themselves, but that's just a guess.
Hope someone has more knowledge than me about this and can help me out.
Thank you!
If you are NEVER going to take these VMs online XP is a better choice. Windows 8.1 (as well as 10) is a recent design and hence is designed for high powered modern hardware, XP was designed long ago for old slower hardware. Running an older OS on newer hardware will allow it to compartively quick, certainly much faster than a new OS on old hardware. Another matter is what programs you will run, if it is old programs they will be compatible with XP, if it is new ones there is a chance XP will not be able to run them. If you are going to take these VMs online then XP is a bad idea, wonderful an operating system as it was it is now becoming insecure due microsoft stopping producing updates to patch holes in it, And do not forget also that Microsoft wouldn't support XP anymore (http://windows.microsoft.com/en-us/windows/end-support-help), so you should go back to the drawing table and fix your priorities and needs and then decide , cheers !
If you cannot run *NIX / BSD Systems you can use WFL windows xp for legacy computers it works on 128 mb RAM
Update: i386 old systems.

Newbie Hypervisor Questions

If I install a bare-metal hypervisor (say, ESXi), would it allow me to run Windows 7 concurrently with Linux?
Would it allow me to run multiple instances of Windows 7?
When I'm sitting at the PC that's running Win7 and Linux on a hypervisor, which OS do I see when I look at the screen? (I'm suspecting that the only way to access either OS is to do a remote login.)
Assuming the answer to #2 is yes, how do you manage multiple installs of Win7 on the same hard drive?
Thanks in advance!
If you simply want to run Linux and Windows in parallel you may of course do this on e.g. ESXi. Still, the OSes would run with virtualized (or emulated) hardware available to them, i.e. you would not be able to easily access all the hardware directly and the hypervisor itself not only introduces an overhead but this overhead is not deterministic.
If you want to run an RTOS (like Real-Time Linux) or any other RTOS, then you need a "real-time hypervisor".
You can google for such hypervisors - there are a few out there.
(I dont want to recommend one here as we are a vendor of such a solution our selves)
Regards
GFL

Simple VM that allows booting from folder or disk

I was wondering if there was a very simple and free virtual machine that would allow you to boot from a folder or disk image that couldn't damage my hard disk. I am using a MacBook and am looking into operating system programming. I found a tutorial on the internet that looked promising. I want to try this but using a VM instead of actually booting from a disk. If I made a folder or disk image containing the boot.bin file and wanted to try the OS I made (while booting from a folder or disk image, not a disk), is there a VM that would let me do it? I have no previous experience with virtual machines. I also want to be sure my hard disk would not be damaged.
If you can make a cdfs .ISO, any VM technology on the market today could do what you ask. VirtualBox, KVM, Xen, VMware, VMware Fusion (on the macbook), etc. Not sure if Parallels can work for you, though.
VMware's products can also boot from floppy images, which are simply binary blobs (for the most part).
On the Mac I think you're limited to VMware Fusion (maybe Parallels), but on Linux you have so many options.
virtualbox (formerly from Sun, now from Oracle) is probably the most powerful VM that you can run on all of Windows, Macs and Linux (OpenSolaris too of course;-) and is at the same time open source (and, of course, also free as in free beer). Whether it supports your new OS is not entirely certain (since it's oriented to supporting a specific list of "guest OS"s and of course your new one isn't there), but, what with it being free, it's surely worth giving it a try.

Virtual Machine Benchmarks

I am using VMware Server 1.0.7 on Windows XP SP3 at the moment to test software in virtual machines.
I have also tried Microsoft Virtual PC (do not remeber the version, could be 2004 or 2007) and VMware was way faster at the time.
I have heard of Parallels and VirtualBox but I did not have the time to try them out. Anybody has some benchmarks how fast is each of them (or some other)?
I searched for benchmarks on the web, but found nothing useful.
I am looking primarily for free software, but if it is really better than free ones I would pay for it.
Also, if you are using (or know of) a good virtualization software but have no benchmarks for it, please let me know.
From my experience of Parallels and VMware (on the PC and more extensively on the Mac) the difference between any 2 competing versions of the software is usually quite small and often 'reversed' in the next releases.
I never found Parallels to be much faster (or slower) than VMware - it often would be a case of the state of the VM I was running, the host machine itself and the app(s) I was running within the VM. If VMWare brought out a new release which did something faster, you could be sure that Parallels would improve their performance in that area in the next release, too.
In the end I settled on VMWare Fusion and the key reason for this was just that it played nicely with VMware Workstation on the PC. I have trouble taking Parallels VMs from the Mac to the PC and back again, and this worked fine on VMware. Finally, though this is less of a concern, I was unhappy that sometimes it felt as if Parallels would release a version without proper regression testing - you'd get the up-to-date version and find that networking was suddenly unexplicably broken until they released another patch a few days later. I doubt this is still the case but VMware always felt a little more 'in control' and professional to me.
I'd go for a solution that you can get running in a stable fashion on your PC, that is compatible with your other requirements (such as your co-workers' platforms and your overall budget). You can waste your lifetime trying to measure which one is faster at any given task!
One other thing - it's worth checking the documentation that comes with the software, and any forums etc, before making judgements about performance. For instance, in my experience throwing huge amounts of ram at your VM (at the expense of free ram in the host system) does NOT automatically make it faster; better to split the ram up evenly, and certainly keep an eye on any recommended figure. In VMware, that recommended figure is a good guide.
You'll get best performance if your hardware supports hardware virtualization, such as AMD's AMD-V or Intel's VT, and you enable this feature on the computer and in your virtualization software.
For Microsoft solutions, you need at least Virtual PC 2007 or Virtual Server 2005 R2 SP1, or Hyper-V on Windows Server 2008 (I don't expect you'll rebuild your system just to run Hyper-V, but I thought I'd mention it).
Subjectively I haven't noticed any difference between Virtual PC and VMware Workstation performance; I'm using VMware now as it supports USB virtualization, which Virtual PC doesn't.
You also generally need to install appropriate custom, virtualization-aware, drivers in the guest OS, as the standard drivers are expecting to talk to real hardware. In Virtual PC and Server these are called Additions, in VMware they are VMware Tools.
Anandtech has some great info on virtualization. Although they are not any benchmarks, it provides a great insight on why it is so difficult to do proper virtualization benchmarks. I cannot suggest you a specific product, because it depends very much on your requirements.