plpbt.img unable to boot MBR

[a_pirard]

VirtualBox is setup to boot plpbt.img from diskette.
The (virtual) HDD contains

• GAG multiboot loader in the MBR
• Ubuntu in a logical partition.

GAG can boot Ubuntu.
But plpbt.img cannot boot GAG because it's not designed to boot the MBR

[Elmar]

yes, it does not start the mbr from the hard disk, it starts the boot sector of the partition

[a_pirard]

No, I am afraid it does not start the PBR.
Because it's a logical partition, I presume.
I only see   HDA PARTITION 1  (there's one unformatted primary)
giving   NO VALID BOOT SECTOR SIGNATURE
I don't see the logical partition (s, there are two, one unformatted).

If plop were booting the MBR, it would do everything the MBR can do.
Which may be something totally different from booting PBRs.
Including using VirtualBox to install and test GAG on an external disk.

[Elmar]

No, I am afraid it does not start the PBR.

when you want to boot from a logical partition, then you have to configure it. the boot manager lists only primary partitions. logical partition are existing in an extended partition -> the extended partition entry is listed too, but not bootable

however, the sentence "it does not start the mbr from the hard disk, it starts the boot sector of the partition" is correct. when the boot manager is configured to use a defined logical partition, then it also starts the boot sector of the logical partition. the mbr is only used when you boot usb.

[a_pirard]

There are good reason to boot the HDD MBR the same way as diskette MBR.
Let us examine that...

For tests, I have setup an all purpose VirtualBox Machine as described in
http://www.papou.byethost7.com/notes/VirtualBox_USB_boot.html
I have found permanently using diskette Plop Boot VERY CONVENIENT.
(you might like using such a setup for your own developments!!!)
Because Plop can boot anything when VirtuaBox starts.  Well, it could...

The virtual HDD contains various beta systems in logical partitions.
The MBR contains GAG multiboot which can boot the extended partitions.
(or other multiboot programs under test)

We agree that Plop cannot boot the MBR.  It's very inconvenient.
Because it cannot boot GAG that can boot extended partitions.

You tell me to configure Plop with the same extended partitions as GAG.
But that is not testing GAG.
Moreover, your program says:   !WARNING!  YOU CANNOT SAVE CHANGES!!!
It would not be convenient to reconfigure that each time you test a boot.

The most convenient and simple is to have Plop Boot manager boot the MBR.
The same way it boots the diskette MBR.

Thanks.

[Dan]

Normally you would just hit escape (or not start plop in the first place) and the BIOS will load the MBR. But I can see how loading the MBR could be useful if you have more than one drive.

[Elmar]

There are good reason to boot the HDD MBR the same way as diskette MBR.

a diskette has no mbr. the first sector is called boot sector.

Moreover, your program says:   !WARNING!  YOU CANNOT SAVE CHANGES!!!
It would not be convenient to reconfigure that each time you test a boot.

plpbt.bin has to be configured with an external program called plpcfgbt.

why? too many reasons to tell it in one sentence.

The most convenient and simple is to have Plop Boot manager boot the MBR.
The same way it boots the diskette MBR.

i had the mbr boot feature long time somewhere in my mind. maybe its time to realize it. the plpbt.bin 5.0.13 will have a new hotkey to boot mbrs of internal hard disks.

[a_pirard]

Thanks !!!
Maybe you'll also want to fix Virtualbox USB 2.0 booting (1.1 is SLOW!!!)
http://forum.plop.at/index.php/topic,200.0.html

[Elmar]

Maybe you'll also want to fix Virtualbox USB 2.0 booting (1.1 is SLOW!!!)
http://forum.plop.at/index.php/topic,200.0.html

currently i have no time for that

[Elmar]

hi,
5.0.13-test5 has now the mbr boot feature
http://www.plop.at/en/bootmanagerdl.html

in the main menu press "q" and the first option boots the mbr of the first internal hard disk.

best regards
elmar

[a_pirard]

5.0.13-test5 has now the mbr boot feature: http://www.plop.at/en/bootmanagerdl.html
in the main menu press "q" and the first option boots the mbr of the first internal hard disk.

That's letter "A", actually    Yes it works.  Great, thanks.
I hope it won't remain qasecret, but that it will show in the main menu !!!
I'm reporting this for everybody's benefit, not just me you know.

Maybe you'll also want to fix Virtualbox USB 2.0 booting (1.1 is SLOW!!!)
http://forum.plop.at/index.php/topic,200.0.html

currently i have no time for that

Some posts in here (about open software) sound like several persons are willing to help you.

Is there another boot manager that will boot USB?

Thanks.  All the best, open-heartedly.

André.