XP 32 bit Memory
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From: Tim Meddick on 6 Dec 2009 19:26 Absolutely no need for "3rd-party boot loaders" as Win7 will easily cope with multi-booting Windows NT-based OSs (although, personally, I have had some problems getting the NT bootloader to boot MS-DOS-based Windows...). == Cheers, Tim Meddick, Peckham, London. :-) "John Callaway" <jcalla(a)erols.com> wrote in message news:jlfnh5pajj95shlpbhfu7vgsdue9ee0kq3(a)4ax.com... > On Mon, 07 Dec 2009 08:34:33 -0400, John John - MVP > <audetweld(a)nbnot.nb.ca> wrote: > >>J. P. Gilliver (John) wrote: >>> In message <883lh59rsnph5s2g2l2lsrbuua3jbui583(a)4ax.com>, "Ken Blake, >>> MVP" <kblake(a)this.is.an.invalid.domain> writes: >>> [] >>>> All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB >>>> address space (64-bit versions can use much more). That's the >>>> theoretical upper limit beyond which you can not go. >>>> >>>> But you can't use the entire 4GB of address space. Even though you >>>> have a 4GB address space, you can only use *around* 3.1GB of RAM. >>>> That's because some of that space is used by hardware and is not >>>> available to the operating system and applications. The amount you can >>>> use varies, depending on what hardware you have installed, but can >>>> range from as little as 2GB to as much as 3.5GB. It's usually around >>>> 3.1GB. >>>> >>>> Note that the hardware is using the address *space*, not the actual >>>> RAM itself. If you have a greater amount of RAM, the rest of the RAM >>>> goes unused because there is no address space to map it to. >>> [] >>> Since the hardware presumably doesn't need much, presumably the RAM >>> _beyond_ the hardware address _could_ be used, if someone were to write >>> a suitable "memory manager" (as used to be done in the early days of DOS >>> to get round the "640k" limit (and even a little around 1M, IIRR). >>> Unless the hardware uses incomplete address decoding, that is. >>> >>> If such a manager were to be written, of course, only software that knew >>> about it could use it (like DOS software that either knew about being >>> "loaded high" or didn't), so there probably would be insufficient >>> usefulness for it to be worth anybody's while, since software houses >>> would be unlikely to cater for it. >> >>That won't happen on NT operating systems, the kernel will simply not >>allow it. >> >>John > > > Ken Blake, > I do appreciate all the info on this matter. I recently > purchased a Dell laptop with W7 OS. I could not install some older > programs on it, so I tried to install XP 32 bit OS on a partition > that I resized with W7. The CD/DVD drive would not fully load the > install disc. I returned the computer. I have since done some research > and found out that if I have XP 32 Bit OS on the computer and then > load W 7 on it, it seems to go better. So I intend to buy another Dell > with W 7 OS, then resize the partition, making room for XP 32 bit OS > on the other partition. I will then Ghost the W 7 partition using > Norton. I will then load XP 32 bit OS over the W 7 OS providing the > CD/DVD will read the XP install disc. Then Ghost the W 7 OS on the > other partition. I have downloaded EasyBC boot loader utility to have > the option to dual boot to which OS I want on boot up. > Ken, am I on the right track? > > John P. Callaway
From: J. P. Gilliver (John) on 7 Dec 2009 03:24 In message <uVdA4PtdKHA.2188(a)TK2MSFTNGP04.phx.gbl>, Tim Meddick <timmeddick(a)gawab.com> writes: >Absolutely no need for "3rd-party boot loaders" as Win7 will easily >cope with multi-booting Windows NT-based OSs (although, personally, I >have had some problems getting the NT bootloader to boot MS-DOS-based >Windows...). > >== > >Cheers, Tim Meddick, Peckham, London. :-) > I wasn't talking about boot loaders, but memory managers. (Which John says won't happen.) > > > >"John Callaway" <jcalla(a)erols.com> wrote in message >news:jlfnh5pajj95shlpbhfu7vgsdue9ee0kq3(a)4ax.com... >> On Mon, 07 Dec 2009 08:34:33 -0400, John John - MVP >> <audetweld(a)nbnot.nb.ca> wrote: >> >>>J. P. Gilliver (John) wrote: >>>> In message <883lh59rsnph5s2g2l2lsrbuua3jbui583(a)4ax.com>, "Ken Blake, >>>> MVP" <kblake(a)this.is.an.invalid.domain> writes: >>>> [] >>>>> All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB >>>>> address space (64-bit versions can use much more). That's the >>>>> theoretical upper limit beyond which you can not go. >>>>> >>>>> But you can't use the entire 4GB of address space. Even though you >>>>> have a 4GB address space, you can only use *around* 3.1GB of RAM. >>>>> That's because some of that space is used by hardware and is not >>>>> available to the operating system and applications. The amount you can >>>>> use varies, depending on what hardware you have installed, but can >>>>> range from as little as 2GB to as much as 3.5GB. It's usually around >>>>> 3.1GB. >>>>> >>>>> Note that the hardware is using the address *space*, not the actual >>>>> RAM itself. If you have a greater amount of RAM, the rest of the RAM >>>>> goes unused because there is no address space to map it to. >>>> [] >>>> Since the hardware presumably doesn't need much, presumably the RAM >>>> _beyond_ the hardware address _could_ be used, if someone were to write >>>> a suitable "memory manager" (as used to be done in the early days of DOS >>>> to get round the "640k" limit (and even a little around 1M, IIRR). >>>> Unless the hardware uses incomplete address decoding, that is. >>>> >>>> If such a manager were to be written, of course, only software that knew >>>> about it could use it (like DOS software that either knew about being >>>> "loaded high" or didn't), so there probably would be insufficient >>>> usefulness for it to be worth anybody's while, since software houses >>>> would be unlikely to cater for it. >>> >>>That won't happen on NT operating systems, the kernel will simply not >>>allow it. >>> >>>John >> >> >> Ken Blake, >> I do appreciate all the info on this matter. I recently >> purchased a Dell laptop with W7 OS. I could not install some older >> programs on it, so I tried to install XP 32 bit OS on a partition >> that I resized with W7. The CD/DVD drive would not fully load the >> install disc. I returned the computer. I have since done some research >> and found out that if I have XP 32 Bit OS on the computer and then >> load W 7 on it, it seems to go better. So I intend to buy another Dell >> with W 7 OS, then resize the partition, making room for XP 32 bit OS >> on the other partition. I will then Ghost the W 7 partition using >> Norton. I will then load XP 32 bit OS over the W 7 OS providing the >> CD/DVD will read the XP install disc. Then Ghost the W 7 OS on the >> other partition. I have downloaded EasyBC boot loader utility to have >> the option to dual boot to which OS I want on boot up. >> Ken, am I on the right track? >> >> John P. Callaway > -- J. P. Gilliver. UMRA: 1960/<1985 MB++G.5AL-IS-P--Ch++(p)Ar(a)T0H+Sh0!:`)DNAf ** http://www.soft255.demon.co.uk/G6JPG-PC/JPGminPC.htm for ludicrously outdated thoughts on PCs. ** Politicians are much like ships: noisiest when lost in a fog.
From: dennis on 7 Dec 2009 15:44 John John - MVP wrote: > That won't happen on NT operating systems, the kernel will simply not > allow it. There is built-in support in the kernel for an application to map unmanaged memory.
From: John John - MVP on 7 Dec 2009 16:00 dennis wrote: > John John - MVP wrote: > >> That won't happen on NT operating systems, the kernel will simply not >> allow it. > > There is built-in support in the kernel for an application to map > unmanaged memory. AWE, only for the applications own use, you can't develop a memory manager around this, the kernel will not allow this to manage other processes' memory. On 32-bit systems AWE will only be able to access RAM above the 4GB barrier if the operating system is PAE capable, 32-bit XP can't do it. Few applications are AWE capable, this is mostly reserved for large database programs and other such applications. John
From: dennis on 7 Dec 2009 16:13
John John - MVP wrote: > AWE, only for the applications own use, you can't develop a memory > manager around this, the kernel will not allow this to manage other > processes' memory. On 32-bit systems AWE will only be able to access > RAM above the 4GB barrier if the operating system is PAE capable, 32-bit > XP can't do it. Few applications are AWE capable, this is mostly > reserved for large database programs and other such applications. > I'm not talking about AWE, but about mapping "device" space (physical memory). That way you can use memory above 4G also in 32bit XP. XP supports PAE. Its own memory manager just doesn't allow access to memory above 4G. |