Re: Multiple OSes on HD?

Paul wrote:
> On 10/24/2021 1:10 AM, Robert Baer wrote:
>>    Is there any reason why one cannot have 4 Primary Partitions, each 
>> with a Win OS (XP, Win7, Win7, Win10)?
>>    Use simple floppy-based boot for OS selection OR the boot partition 
>> has the selection program?
>>
>>     Thanks,
>> R. Baer
>>
> 
> Can be done.
> 
> Set the BIOS SATA port to the non-AHCI setting,
> as otherwise, the four OSes can't play nice together.
> 
> To do a SATA AHCI install for WinXP, requires pressing
> F6 early on and presenting a txtsetup.oem class floppy diskette.
> WinXP has no "MSAHCI" driver built-in like the other OSes do.
> 
> And that's why you have to make an intelligent choice for
> disk operating mode, before the project starts. Lots of
> my installed OSes here, are already AHCI, which would
> complicate making the project disk in this case. If the
> machine was brand new, and no other OSes had ever been
> installed, I could select the non-AHCI choice in the BIOS
> and all of the listed OSes should be happy with that.
> 
> AHCI supports tagged command queuing, which means commands
> can be completed by the disk drive out of order. This only
> pays off, if the "disk queue" grows, which may not be
> the case in light usage of a PC. Only a server application
> has a consistent disk queue, 24 hours a day.
> 
> Install
> 
>     WinXP first
>     Win7 second
>     Win8 next
>     Win10 next
> 
> I created four primary partitions, all NTFS, before I started.
> Used Custom in the installer, clicked on the partition
> I wanted it to use for the C: in that case.
> 
> The BCD file that the last three use, should have
> options for chain loading the WinXP OS.
> 
> Your WinXP might not have a "skip" button for skipping
> past the license key entry. Look around for something
> suited to passing key validation (but not suited to
> actual activation when install is finished). You might
> have to use material from here, to pass the key entry step
> of the WinXP SP3 disc.
> 
> https://gist.github.com/denizssch/72ec2aa1c5d0a84ffb57076f7dbf30d6
> 
> Win7 should have a "skip" button.
> 
> Win8 needs an install-only key, as it has no "skip",
> but there are some known install-only keys available.
> At one time, I tested that one of these worked, and I
> replaced the key with the purchased key later and it
> activated OK with my purchased key. Using a fake key
> at first, doesn't hurt the eventual disposition of the
> OS.
> 
>     Windows 8.0 Pro:   XKY4K-2NRWR-8F6P2-448RF-CRYQH
>     Windows 8.0 Core:  FB4WR-32NVD-4RW79-XQFWH-CYQG3     # Core = "Home"
> 
>     Windows 8.1 Pro:   XHQ8N-C3MCJ-RQXB6-WCHYG-C9WKB
>     Windows 8.1 Core:  334NH-RXG76-64THK-C7CKG-D3VPT     # Core = "Home"
> 
> Win10 has a "skip" key.
> 
> As a result, there should be enough materials to do it.
> 
> The only gating issue then, is deciding what to do with
> the SATA interface setting. If you had a SCSI drive on a
> Perc, who knows, it might work with no intervention
> whatsoever :-)
> 
> Naturally, the project is also gated by meeting the
> hardware requirements of all OSes. If the machine does
> not meet Win10 instruction set requirements, then it's
> not going to install.
> 
> If you use your "spacer" partitions wisely, all the
> OSes can be convinced to use exactly one partition
> each. If the partition table is full at the start,
> the Installer behavior is quite tame (for a change).
> 
>    [Picture]
> 
>    https://i.postimg.cc/RZK0nD1M/four-os-setup.gif
> 
> By not giving the OSes the partitions they want:
> 
> 1) Bitlocker FDE doesn't work right. A separate partition
>     is used, so C: can be encrypted. The partition with the
>     BCD file on it, is unencrypted (so the machine can boot).
> 
> 2) ReagentC won't work right. If ReagentC WinRE.wim is kept
>     on a separate partition, that makes it easier for the
>     modern OSes to repair themselves. If C: is corrupted and
>     it is the only partition, then the WinRE.wim would be
>     inaccessible.
> 
>   Paul
   Thanks!
   Looks easier than I thought.


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