---
name: "mmc_format"
section: "8"
platform: "linux"
package: "udfclient"
version: "0.8.11-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/mmc_format"
---

# mmc\_format(8)

format optical media

## NAME

**mmc\_format** – format optical media

## SYNOPSIS

**mmc\_format** \[**-BDFGHhIMOpRrSsw**\] \[**-b** *blockingnr*\] \[**-c** *cert-num*\] *special*

## DESCRIPTION

The **mmc\_format** utility formats optical media conforming to the MMC standard. This includes CD, DVD, and Blu-Ray (BD) media.

The options are as follows:

- **-B**

  Blank media when possible before formatting it.

- **-b** *blockingnr*

  Explicitly select packet size in sectors (for CD-RW only). It is not recommended to change this from its default of 32.

- **-c** *cert-num*

  Certify media for DVD-RAM / DV-RE. The argument cert-num specifies:

  - 0

    no certification

  - 1

    full certification

  - 2

    quick certification

- **-D**

  Debug mode. Print all SCSI/ATAPI command errors.

- **-F**

  Format media.

- **-G**

  Grow last CD-RW/DVD-RW session.

- **-H**

  Show help and print formatting choices for the inserted media.

- **-h**

  Show help and print formatting choices for the inserted media.

- **-I**

  Show help and print formatting choices for the inserted media.

- **-M**

  Select MRW (Mount Rainier) error correcting background format.

- **-O**

  Old style CD-RW formatting; recommended for CD-RW.

- **-p**

  Explicitly set packet format.

- **-R**

  Restart previously stopped MCD-MRW or DVD+RW background format.

- **-r**

  Recompile defect list for DVD-RAM.

- **-S**

  Grow spare space DVD-RAM / BD-RE.

- **-s**

  Format DVD+MRW / BD-RE with extra spare space.

- **-w**

  Wait until completion of background format.

## NOTES

Due to the enormous varieties in optical media, **mmc\_format** is made as generic as possible. This can result in confusion.

## EXAMPLES

```
mmc_format -B -O /dev/rcd0d
```

Blanks and then formats a CD-RW disc using the “old style” format command. It is recommended to use this “old style” command unless your drive reports that it's not supported; in that case, resort to the default **-F**. Note that a CD-RW disc can be reformatted without being blanked. Blanking switches between sequential and fixed packet writing by erasing the disc. This can also help to revive old discs.

```
mmc_format -F -M /dev/rcd0d
```

Format a CD-RW or a DVD+RW to use MRW (Mount Rainier). This format tries to hide media flaws as much as possible by relocation.

## SEE ALSO

scsictl(8)

## HISTORY

The **mmc\_format** command first appeared in NetBSD 5.0.

## AUTHORS

Reinoud Zandijk ⟨*reinoud@NetBSD.org*⟩

## BUGS

**mmc\_format** could be merged with scsictl(8) but that tool is very hard disk oriented.