Re: [List] Re: dd if=/dev/rdisk12 of=/dev/zero (OT, since macOS)
Date: Mon, 03 Nov 2025 13:43:19 UTC
On 02/11/2025 10:56, Christoph Kukulies wrote: > The dd is working on the character device, not block device. > I tried it out on a CD on my Mac right before: > > cr--r----- 1 root operator 0x1000032 Nov 2 11:35 rdisk14s0 > > cr--r----- 1 kuku operator 0x1000031 Nov 2 11:35 rdisk14 > > br--r----- 1 root operator 0x1000032 Nov 2 11:35 disk14s0 > > br--r----- 1 kuku operator 0x1000031 Nov 2 11:35 disk14 > > > > e.g: > > Christophs-MBP:~ root# dd if=/dev/rdisk14s0 of=/dev/null bs=2048 count=2 > > 2+0 records in > > 2+0 records out > > 4096 bytes transferred in 1.509344 secs (2714 bytes/sec) > > Christophs-MBP:~ root# > > This is a FreeBSD vs Mac compatibility issue. On a Mac you can actually write to /dev/zero as well as reading from it as long as you know the password. With FreeBSD the only bitbucket is /dev/null unless you're using zfs, in which case you can create a zvoid device - a bit like a zvol but write-only. It's very popular with organisations that need to keep files for a long time buyt never want to read them. Linux has a similar filing system called btrfs, but it's buggy and occasionally you can read some of the files back at a later date. But your big mistake was going for the 10Tb model. For an extra $5 the 25Tb version is much faster and doesn't have this problem. Regards, Frank.