Is the wheezy 2.7 build broken?

On my Mac I do not have a choice. As soon as the Dd finishes, the machine tries to mount the stick and that is when I get the error dialog.

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Pardon my ignorance. I'm definitely a computer person, but Linux is not my forte (obviously!)... Are you saying that there might be something wrong with the image then? If so, I'll cancel my appointment with the psychiatrist that I have for this afternoon!

I think I'm reading that I should have been able to boot from the stick/CD but that there were some issues that still render the ISO flawed or incomplete.

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Shoot.... Psychiatrist at noon it is, then....

Thanks for clarifying.

OK, I pulled out my Ubuntu 16.04 LTS Linux box. There is no 'right click' and burn to disc option on this machine (verified myself and through internet searching. So, I downloaded Brasero and Burned the ISO image to a DVD (too big for a CD). Before doing this, I double checked the MD5 to ensure it matched that on the distro site. The burn was successfully verified and the DVD drive popped open.

I then took this drive and put it into my Mac. It "thought" for a bit and came back with the "I can't read this disc" message. I groaned. I put the drive back into the Linux machine that burned the disc and I was able to read it. I did not try to boot the disc.

Next, I took the disc to my target CNC and tried to boot. In the BIOS boot menu the DVD was not identified. Frustrated, I shut everything down and disconnected the hard drive and powered up again. The only device was the DVD at that point....

Anndddd.... It failed to boot. There was a message:
isolinux.bin missing or corrupt

I am thoroughly frustrated with something that should be brain dead simple. But I've tried this on three Macs, two Linux boxes (both Ubuntu), both DVD media and USB sticks. NOTHING seems to produce a bootable DVD.

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To be honest, I haven't tried the USB stick again. I ran into enough issues that I needed to give it a bit of a break. But I have now run the MD5 on the DVD when it is installed into the Linux machine that created the disc. I get the same MD5 checksum that you have in your message.

I do have my first success. The DVD does boot on the Linux box upon which it was created. So, clearly that is working. This presents a very curious situation for me as the MB in the target milling machine (the Asus MB) absolutely was able to boot one of the older distributions of LinuxCNC from 3 or 4 years ago (built on Ubuntu, don't readily have the version). That OS/LinuxCNC is still running on the MB but I wanted to upgrade to the latest.

Regarding Brasero (although probably academic now that I have confirmed booting on my Linux laptop (T61p)... I think it did the checksum first but I can't confirm that. At some point it definitely did perform the MD5 though.

[on edit]
USB stick on the target... Yes, I did try the smaller stick last night but I did not have any success. Now that I have a booting DVD on my T61p, I'll probably try to create a bootable USB with the ISO on that and see what happens. I'm reserving judgement on that particular device though. While I'm sure my 16gB is fine, the 2GB is giving me pause. I'm starting to have issues with it even within a single computer, so I think I may trash the device. Unfortunately I don't have any other 2GB USB sticks... I may have to go buy one. Then again, I know the DVD works now so it could be academic.

A little success is what I needed. I feel much better now, although I certainly would like to quantify what is going on still. Needless to say, your help is greatly appreciated.

I stopped by the local computer store and picked up a KINGSTON 8GB stick. That was the smallest one they had. I then proceeded to execute the same command as provided in the download area of LinuxCNC:

dd if=linuxcnc-2.7-wheezy.iso of=/dev/sdb1

This worked for a bit and exited without any abnormal behavior (displayed some information but no errors). I am able to mount the drive on my T61p Linux machine and read the contents. In other words, I can see all of the data from the ISO. Great...

I then tried to reboot the same T61p laptop with the 8GB stick still attached. This results in an error and I am informed that no operating system is present...

It is almost as though the boot loader is not present or something. I was quite careful to use the exact same dd (except for the destination, which is sdb1 for me, based on df) as is presented in the installation guide. Frankly, I have run out of options. I can't really think of how else to attack this problem.

I managed to find a 2GB device. Like the 8GB, I wrote it with my 16.04 LTS Ubuntu. Mounted the disk and could see it. The computer (T61p) couldn't boot from either disk. Tried to boot on my target Asus motherboard and was presented with a 'no operating system found' with both sticks.

I'm literally getting to the point where I'm wondering if I can pull the HD on the target machine and somehow load everything onto it from one of the other machines. That seems kind of crazy but I can't think of anythng else to try

Ideas?

INCORRECT:
dd if=linuxcnc-2.7-wheezy.iso of=/dev/sdb1
You are writing to just a partition

CORRECT:
dd if=linuxcnc-2.7-wheezy.iso of=/dev/sdb
This will write "to the whole disk"

It will also wipe any data and partition information already on the disk.

Pay careful attention to the difference in the commands. This is clearly shown here:
linuxcnc.org/docs/2.7/html/getting-start...to_a_bootable_device

The fact that one machine can boot from the dvd and the other can't makes me suspect a hardware issue with the machine that can not boot from the dvd. Sort that machine out so that it does recognise both the dvd and hdd.

The image is 100% fine as is, there is no issue with it.