How to boot ISO file directly (not from CD)?

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nic007
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How to boot ISO file directly (not from CD)?

#1 Post by nic007 »

I need some confirmation here. Some programs can boot puppy directly from the ISO file. Generally (or in earlier days), the procedure would be to make an ISO which would then be burnt to CD. The bootloader would be isolinux.bin and the default configuration file would have pmedia=CD. What I want to know is would this default setting work when using one of these programs to boot from ISO directly (not CD) OR if the configuration file will have to be changed to indicate different media?

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bigpup
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#2 Post by bigpup »

pmedia=cd is just going to control how the Puppy boot process adjusts to the device the install is on.
The basic difference is Puppy will boot as if it is installed on a CD.

There are some specific ways it loads into memory and how it searches for the save, but they do not have an affect on basic boot-up.
It will still boot to a good working Puppy.

The programs you are talking about, that will boot from an iso, are not going to know about the different pmedia= options Puppy can use.
The pmedia= is not going to be changed by them.

Puppy specific installers and Grub4dos boot loader, do know how to make the change of pmedia= to reflect what device Puppy is booting from.
The things they do not tell you, are usually the clue to solving the problem.
When I was a kid I wanted to be older.... This is not what I expected :shock:
YaPI(any iso installer)

watchdog
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#3 Post by watchdog »

I often boot puppy's isos by grub2 and I can access the frugal installations on atahd or usbhd. Example:

Code: Select all

menuentry "Wary 5.5 ISO" {
set root=(hd0,1)
loopback loop /wary-5.5.iso
linux (loop)/vmlinuz pmedia=atahd psubdir=wary55 pfix=fsck
initrd (loop)/initrd.gz
}

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nic007
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#4 Post by nic007 »

So, these iso booter programs will be able to boot the ISO even if the media is stipulated as CD? Anyways - I've read that Puppy uses hybrid ISO since 2013 which actually answers the question as the dd command can be used to make the iso bootable for other media like usb flash drive. The reason why I asked the question was to make sure that the mkisofs command used in the builtin remaster script (with default configuration settings) would produce a "flexible" iso file.

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bigpup
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#5 Post by bigpup »

So, these iso booter programs will be able to boot the ISO even if the media is stipulated as CD?
Yes.
Again, it will only make Puppy boot as if it was installed on a CD.

However, as watchdog shows.
He uses a different boot loader, that has the pmedia= corrected for the device it is booting from.
I assume he manually made that change to the boot entry.
The things they do not tell you, are usually the clue to solving the problem.
When I was a kid I wanted to be older.... This is not what I expected :shock:
YaPI(any iso installer)

jafadmin
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Joined: Thu 19 Mar 2009, 15:10

Re: How to boot ISO file directly (not from CD)?

#6 Post by jafadmin »

nic007 wrote:I need some confirmation here. Some programs can boot puppy directly from the ISO file. Generally (or in earlier days), the procedure would be to make an ISO which would then be burnt to CD. The bootloader would be isolinux.bin and the default configuration file would have pmedia=CD. What I want to know is would this default setting work when using one of these programs to boot from ISO directly (not CD) OR if the configuration file will have to be changed to indicate different media?

Nope, boot CD iso's as CD's. You can use either Grub2 or Grub4Dos.

ITSMERSH

#7 Post by ITSMERSH »

Why should I want to boot from .iso?
What is the benefits?

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nic007
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#8 Post by nic007 »

ITSMERSH wrote:Why should I want to boot from .iso?
What is the benefits?
I can think of a few. Quickly testing a bunch of distributions / it remains a convenient way of distributing the OS / could save disk space ( for instance I have frugal installs but also keep the official ISO's. This shouldn't be necessary).

watchdog
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#9 Post by watchdog »

ITSMERSH wrote:Why should I want to boot from .iso?
What is the benefits?
An old bug of puppy was the main sfs not found in some frugal installs on quirky hardware. I have found that booting the iso can solve the problem in most cases.

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Mike Walsh
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#10 Post by Mike Walsh »

@ nic007/watchdog:-

Explain one thing to me, if you will. I remember hearing about this on the Ubuntu Forums, when I was a member there.....and even all those years ago, I didn't understand how it could be possible.

How can you boot from an ISO, without a non-volatile storage medium to hold the data during the boot process? RAM, as we all know, is what's termed 'volatile memory'; in other words, it requires power to it at all times in order to hold anything.

Now, correct me if I'm wrong (and I'm not saying this process isn't possible, since like I said, I don't understand it), but.....surely, if you're trying to do this, at the very moment of re-booting, for a split-second, your RAM loses its power; so, hasn't the data you're attempting to boot with just gone 'poof' into thin air?

An old dog who's trying to understand something that seems to be impossible..!


Mike. :wink:

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nic007
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#11 Post by nic007 »

Mike Walsh wrote:@ nic007/watchdog:-

Explain one thing to me, if you will. I remember hearing about this on the Ubuntu Forums, when I was a member there.....and even all those years ago, I didn't understand how it could be possible.

How can you boot from an ISO, without a non-volatile storage medium to hold the data during the boot process? RAM, as we all know, is what's termed 'volatile memory'; in other words, it requires power to it at all times in order to hold anything.

Now, correct me if I'm wrong (and I'm not saying this process isn't possible, since like I said, I don't understand it), but.....surely, if you're trying to do this, at the very moment of re-booting, for a split-second, your RAM loses its power; so, hasn't the data you're attempting to boot with just gone 'poof' into thin air?

An old dog who's trying to understand something that seems to be impossible..!


Mike. :wink:
The RAM problem you are describing may occur whilst loading anything at bootup, iso or not (from any medium). Something will be loaded into RAM, so if that problem occurs, the bootup will almost certainly be unsuccessful. You will have to reboot.

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Burn_IT
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#12 Post by Burn_IT »

Anything carried over from one boot to the next must have been stored either in a piece of non-volatile memory that wasn't refreshed, or on some sort of storage media as a temporary file.

Also don't forget that nowadays there are different levels of "boot" that perform different levels of clearing out and resetting devices that may allow data to be preserved in buffers etc.
"Just think of it as leaving early to avoid the rush" - T Pratchett

patrick21
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#13 Post by patrick21 »

Hello,

I think this way to boot on an iso (without cd) an interesting experiment. But, since I never used grub 2, I din't find out how to enter and adapt the script watchdog gave us.

Is there a more simple entry with grub4dos? For an iso on a usb stick?

Thanks you.

watchdog
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#14 Post by watchdog »

The easy way you can experiment with cautions with this is to use the old grub-1.98-i486.pet by rcrsn51 now retired and which I shared at:

http://www.murga-linux.com/puppy/viewto ... 618#933618

Install grub2 in sda by:

Code: Select all

grub-install --force --no-floppy --root-directory=/mnt/home /dev/sda
Then install again grub4dos in sda. You can use now grub2 by the advanced menu of grub4dos ("Find grub2"). Move /root/grub.cfg in /mnt/home/boot/grub/ and edit grub.cfg to fit your case. The original grub.cfg has some old examples in it which you can delete.

If you are going to experiment with grub4dos then you have to read the long thread about isobooter. Grub4dos can boot an iso file from an usb stick but it might be freshly formatted before copying the iso into it.

patrick21
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#15 Post by patrick21 »

watchdog thank you.

I'll try all this and feed back here for those who might be interested.

patrick21
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Joined: Sat 09 Aug 2014, 04:13

#16 Post by patrick21 »

I think I have missed something because for the moment, I can't do it. I'll try again...

Anyway, thank you!

patrick21
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Joined: Sat 09 Aug 2014, 04:13

#17 Post by patrick21 »

Hello,

I found out that Legacy Grub 2013 is installed on my puppy precise. It works, but the syntax of the menu is similar to Grub4dos

(near to this)

Code: Select all

title Puppy precise 5.7.3
  uuid C060-52D4
  kernel /Puppy_precise_5.7.3/vmlinuz  pmedia=usbflash psubdir=Puppy_precise_5.7.3 pfix=fsck
  initrd /Puppy_precise_5.7.3/initrd.gz

with this syntax, in order to boot on an iso, I don't know how to enter the menu given by Watchdog, which syntax is different. In my case, it should be:

Code: Select all

menuentry "Puppy Precise ISO" {
set root=(hd0,1)
loopback loop /Puppy_precise.iso
linux (loop)/vmlinuz pmedia=atahd psubdir=wary55 pfix=fsck
initrd (loop)/initrd.gz
}

which is the syntax of Grub 2 installed from the pet. But even doing about all that was written here, I only manage to get the message (dos I presume)

Code: Select all

grub>
without any menu.

I guess that legacy grub installed is giving some problem to use Grub 2. I'll try to uninstall it before to go on.

I read the thread of rcsn about isobooter. It is a possibility. But I thought that watchdog's method was simpler (when it works, of course).

I'll continue my experiments.

watchdog
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Location: Italy

#18 Post by watchdog »

Grug legacy and grub4dos use a different syntax: grub2 (I provided a grub-1.98 pet package to install it in your puppy) has its own syntax. I suggest the following steps to build a usb stick which boots the iso of precise puppy by grub2:

1-Install grub-1.98-i486.pet in a working precise puppy install.

2-Attach a usb stick sdb1 to your pc. In console:

Code: Select all

gparted
Pay attention to select the correct device sdb and format it say ext2 with boot flag. If you have trouble to understand "gparted" do not do anything and STOP HERE.

3-Mount sdb1 and copy the iso file of precise puppy to the usb stick.

4-Type in console:

Code: Select all

grub-install --force --no-floppy --root-directory=/mnt/sdb1 /dev/sdb
5-Move /root/grub.cfg in /mnt/sdb1/boot/grub/grub.cfg.

6-Edit /mnt/sdb1/boot/grub/grub.cfg to show only:

Code: Select all

set timeout=10
set default=0

menuentry "Precise puppy ISO" {
 set root=(hd0,1)
 loopback loop /precise-5.7.1.iso
 linux (loop)/vmlinuz pmedia=usbflash pfix=fsck
 initrd (loop)/initrd.gz
}
7-Mount precise-5.7.1.iso by clicking on it and copy the main sfs standing alone to /mnt/sdb1/

8-Boot the usb stick.

**************

If you use a freshly formatted usb stick you can copy the iso file of precise puppy to it so that it is "contiguous", install grub4dos to it and use something like:

Code: Select all

title Puppy precise ISO on sdb1
    map (hd1,0)/precise-5.7.1.iso (hd32)
    map --hook 
    root (hd32)
    chainloader (hd32)
    boot
More informations about isobooter by this way in rcrsn51's HowTo:

http://murga-linux.com/puppy/viewtopic.php?t=67235

patrick21
Posts: 43
Joined: Sat 09 Aug 2014, 04:13

#19 Post by patrick21 »

Hello,

watchdog, thank you.

For a mysterious reason, the entry for my puppy precise iso (I copied from your post) in the grub menu does not appear (the others, Ubuntu, mint etc I left appear).

There is a progress, because before, the whole menu of grub was not appearing (but I put only the entry for precise. It might be the reason).

watchdog, I don't want to take your time with this. From time to time I'll continue searching what is wrong in my case. Maybe I'll find out. If not, no problem

Thanks.

By the way, I don't have any problem with gparted. I am used also to mount isos and copy the files on usb sticks in order to install new puppies. I just thought interesting to know how to boot on an sole iso.

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