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hdiutil notes: Difference between revisions
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→Create a RAM drive: somehow i fucked up the grammar here
(→Create a RAM drive: somehow i fucked up the grammar here) |
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== Create a loop device == | == Create a loop device == | ||
Similar to losetup for Linux, this allows setting up a {{iw|wikipedia|loop device}} for any file. Usually hdiutil tries to determine how to attach the file based on the file extension and contents. | Similar to losetup for Linux, this allows setting up a {{iw|wikipedia|loop device}} for any file. Usually hdiutil tries to determine how to attach the file based on the file extension and contents, so we need to force it to assume a raw disk with <code>-imagekey diskimage-class=CRawDiskImage</code>. | ||
<pre> | <pre> | ||
hdiutil attach -imagekey diskimage-class=CRawDiskImage -nomount myfile.bin | hdiutil attach -imagekey diskimage-class=CRawDiskImage -nomount myfile.bin | ||
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Create a {{iw|wikipedia|RAM drive}}. The value is the amount of 512-byte sectors, so 8388608 * 512 = 4294967296 or 4.0 GiB. | Create a {{iw|wikipedia|RAM drive}}. The value is the amount of 512-byte sectors, so 8388608 * 512 = 4294967296 or 4.0 GiB. | ||
The drive is not pre-formatted, therefore <code>-nomount</code> is required, or else hdiutil will newly-created drive | The drive is not pre-formatted, therefore <code>-nomount</code> is required, or else hdiutil will scan the newly-created drive for partitions, find none because it's completely blank, and cancel attaching. | ||
<pre> | <pre> | ||
hdiutil attach -nomount ram://8388608 | hdiutil attach -nomount ram://8388608 | ||
</pre> | </pre> | ||
After attaching it can be formatted with any tool, such as diskutil, Disk Utility, or newfs_*. | After attaching it can be formatted with any tool, such as diskutil, Disk Utility, or newfs_*. | ||
{| class="wikitable" | |||
|+ Table of common sizes for quick access | |||
! Disk size | |||
! In bytes | |||
! In sectors | |||
! hdiutil command | |||
|- | |||
| 1 GiB | |||
| 1073741824 | |||
| 2097152 | |||
| <code>hdiutil attach -nomount ram://2097152</code> | |||
|- | |||
| 2 GiB | |||
| 2147483648 | |||
| 4194304 | |||
| <code>hdiutil attach -nomount ram://4194304</code> | |||
|- | |||
| 3 GiB | |||
| 3221225472 | |||
| 6291456 | |||
| <code>hdiutil attach -nomount ram://6291456</code> | |||
|- | |||
| 4 GiB | |||
| 4294967296 | |||
| 8388608 | |||
| <code>hdiutil attach -nomount ram://8388608</code> | |||
|- | |||
| 5 GiB | |||
| 5368709120 | |||
| 10485760 | |||
| <code>hdiutil attach -nomount ram://10485760</code> | |||
|- | |||
| 6 GiB | |||
| 6442450944 | |||
| 12582912 | |||
| <code>hdiutil attach -nomount ram://12582912</code> | |||
|- | |||
| 7 GiB | |||
| 7516192768 | |||
| 14680064 | |||
| <code>hdiutil attach -nomount ram://14680064</code> | |||
|- | |||
| 8 GiB | |||
| 8589934592 | |||
| 16777216 | |||
| <code>hdiutil attach -nomount ram://16777216</code> | |||
|} | |||
== <tt>create -srcfolder</tt> doesn't preserve creation time == | == <tt>create -srcfolder</tt> doesn't preserve creation time == | ||
Still does this as of | Still does this as of Ventura. Creation time is reset to modified time. This isn't really an issue unless you're like me and want to preserve as much info as possible. | ||
Currently the only way I found around this is to manually copy the files in Finder. Maybe there's another command-line tool to preserve this data. Either way though, it means the disk image needs to be manually created with the right size. | Currently the only way I found around this is to manually copy the files in Finder. Maybe there's another command-line tool to preserve this data. Either way though, it means the disk image needs to be manually created with the right size. | ||
