Hi, Kent West wrote: > The Yosemite Mac's Disk Utility gives me more info > "This disk is not writable and can't be partitioned" > that the Write Status is Read Only,
It really looks like this info comes from the stick's firmware and is not fabricated by a software layer of the operating system. I looked for the possible reason of EROFS in Linux driver sd.c. Function sd_read_write_protect_flag() does its best to get a Mode Parameter Header that preceeds any SCSI mode page reply. Then it interprets the "Device-Specific Parameter" byte in that 4-byte header. Standard SBC-2 says in section 6.1.3 that if bit 7 of this byte is set then the medium is write protected. I see this test in line 2638 of https://github.com/torvalds/linux/blob/master/drivers/scsi/sd.c as sdkp->write_prot = ((data.device_specific & 0x80) != 0); So like with the "No medium" error, it looks like an ill drive. (I always thought that optical drives are a bit bitchy. But disk devices have their own ways to surprise the programmer. I better stay with the opticals and in userspace. :)) > It's just really odd that two differently-manufactured/aged sticks went bad > at the same time, when trying to do the same operation with them, My best explanation is that copying the 2 GB was more work than they had to do in the years before. Others are that misery loves company and misfortune seldom comes alone. Already yesterday i dd'ed the ISO onto a 4 GB SanDisk Cruzer stick in order to look for problems with mounted partitions. (None found.) The stick is still alive and writable. So debian-live-9.2.0-amd64-cinnamon.iso is not poisonous to all sticks. I can hardly imagine how the computer should be to blame. It could possibly fry the stick's controller. But talking it into losing its medium or making it read-only ? > Looks like I'll be tossing these sticks. If you buy a new one, then make a backup before putting the ISO on it: dd if=/dev/sdc bs=1M | gzip >new_stick_backup.gz A virgin stick should yield quite a small .gz file. Have a nice day :) Thomas
