Creating a bootable USB stick - what in /dev?

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DrDave
Posts: 49
Joined: 2020/03/12 10:23:33

Creating a bootable USB stick - what in /dev?

Post by DrDave » 2021/01/18 16:33:34

I want to create a bootable USB stick in CentOS 7.9 I found this webpage

https://wiki.centos.org/HowTos/InstallFromUSBkey

but it uses as an example

dd if=CentOS-6.5-x86_64-bin-DVD1.iso of=/dev/sdz

The problem I have, is I don't know what to put in place of "sdz"

Looking in /var/log/messages I see

Jan 18 15:53:07 duck kernel: usb 2-8.2: new SuperSpeed Gen 1 USB device number 4 using xhci_hcd
Jan 18 15:53:07 duck kernel: usb 2-8.2: New USB device found, idVendor=30de, idProduct=6545, bcdDevice= 1.10
Jan 18 15:53:07 duck kernel: usb 2-8.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jan 18 15:53:07 duck kernel: usb 2-8.2: Product: TransMemory
Jan 18 15:53:07 duck kernel: usb 2-8.2: Manufacturer: KIOXIA
Jan 18 15:53:07 duck kernel: usb 2-8.2: SerialNumber: C03FD5F770FBE4207312345E
Jan 18 15:53:07 duck kernel: usb-storage 2-8.2:1.0: USB Mass Storage device detected
Jan 18 15:53:07 duck kernel: scsi host10: usb-storage 2-8.2:1.0
Jan 18 15:53:08 duck kernel: scsi 10:0:0:0: Direct-Access KIOXIA TransMemory PMAP PQ: 0 ANSI: 6
Jan 18 15:53:08 duck kernel: sd 10:0:0:0: [sdd] 30265344 512-byte logical blocks: (15.4 GB/14.4 GiB)
Jan 18 15:53:08 duck kernel: sd 10:0:0:0: [sdd] Write Protect is off
Jan 18 15:53:08 duck kernel: sd 10:0:0:0: Attached scsi generic sg4 type 0
Jan 18 15:53:08 duck kernel: sd 10:0:0:0: [sdd] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
Jan 18 15:53:08 duck kernel: sdd: sdd1
Jan 18 15:53:08 duck kernel: sd 10:0:0:0: [sdd] Attached SCSI removable disk


Looking in /dev, I see

brw-rw----. 1 root disk 8, 48 Jan 18 15:53 sdd
brw-rw----. 1 root disk 8, 49 Jan 18 15:53 sdd1



Should I use /dev/sdd1 or /dev/sdd or something else? Clearly this is not a case of "suck it and see", as it will seriously mess up the system, if one needs to be root. I don't know if one needs to be root or not. That page does not mention it, but it would not surprise me if one needs to be.

Dave

DrDave
Posts: 49
Joined: 2020/03/12 10:23:33

Re: Creating a bootable USB stick - what in /dev ?

Post by DrDave » 2021/01/18 17:04:15

Okay, one does need to be root

[drkirkby@duck ~]$ dd if=CentOS-7-x86_64-Everything-2003.iso of=/dev/sdd
dd: failed to open ‘/dev/sdd’: Permission denied
[drkirkby@duck ~]$ dd if=CentOS-7-x86_64-Everything-2003.iso of=/dev/sdd1
dd: failed to open ‘/dev/sdd1’: Permission denied


so clearly I need to get it right, as I don't want to make an error as root.

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TrevorH
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Re: Creating a bootable USB stick - what in /dev ?

Post by TrevorH » 2021/01/18 17:08:48

You need to use the entire device (sdd) not sdd1.
CentOS 6 died in November 2020 - migrate to a new version!
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 is dead, do not use it.
Full time Geek, part time moderator. Use the FAQ Luke

tunk
Posts: 896
Joined: 2017/02/22 15:08:17

Re: Creating a bootable USB stick - what in /dev ?

Post by tunk » 2021/01/18 18:35:35

Run this as root to figure out what device to use:
fdisk -l

Whoever
Posts: 1171
Joined: 2013/09/06 03:12:10

Re: Creating a bootable USB stick - what in /dev ?

Post by Whoever » 2021/01/19 04:18:43

TrevorH wrote:
2021/01/18 17:08:48
You need to use the entire device (sadd) not sdd1.
Just to be entirely clear, Trevor typoed his post. That should be "sdd", not "sadd".

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