How to format and erase Flash in a Cisco router

Before you can use a new Flash memory card, you must format it.

Different commands are required to format and erase Flash memory depending on the type of filesystem running on the router.

Class A and Class C filesystems issue the format command.

Class B filesystems issue the erase command.

This is the Class A filesystem:

	Cisco 12000 Series Internet Router
	Cisco 7000 Route Switch Processor (RSP)
	Catalyst 8500 Switch Route Processor (SRP)
	Cisco 7500 Series RSPs (RSP 2, RSP 4, RSP 8)
	Cisco 6400 Universal Access Concentrator (UAC)
	Catalyst 5000 and 5500 Route Switch Module (RSM)
	Multiservice Switch Route Processor (MSRP) for LightStream 1010
	ATM switch and processor for LightStream 1010 and Catalyst 5000 and 5500

This is the Class B filesystem:

Cisco 1000 series routers

The 1600 series router has a single PC card that contains Flash memory.

The 1601 to 1604 run from Flash.

If you remove the PC card when the router is running, the router halts.

The 1601R to 1605R run from RAM.

If you remove the PC card, the router does not load the Cisco IOS Software image during the next bootup.

In the 1600 series, you cannot delete the running image file or any other file unless it is in a different partition.

The 3600 series routers traditionally uses a Class B filesystem.

However, with the addition of crash information file support in Cisco IOS Software version 12.2(4)T, the 3600 needs the ability to delete individual files.

Consequently, the 3600 series routers with Cisco IOS Software version 12.2T and later utilize commands from Class B filesystems as well as commands from Class C filesystems.

To activate the Class C filesystem commands on the 3600 with Cisco IOS Software Release 12.2T, issue the erase command to completely remove all files from the Flash filesystem.

When the Flash is empty, issue the squeeze command against it to create a squeeze log.

At this point, the 3600 Flash system issues the delete and squeeze commands like a Class C filesystem.

This is the Class C filesystem:

	AS5800 Dial Shelf Controller (DSC)
	Catalyst 5000 and 5500 Supervisor III Module
	Catalyst 6000 and 6500 Supervisor Engine I
	Catalyst 6000 and 6500 Supervisor Engine II
	Cisco 7000 Route Processor
	Cisco 7100 series routers
	Cisco uBR7100 series routers
	Cisco 7200 Series Network Processing Engine
	Cisco uBR7200 series routers
	Cisco 7200VXR Series Network Services Engine 1
	Cisco 7600 Series Internet Routers
	Cisco 10000 series routers (Edge Services Router (ESR))
	Cisco uBR10000 series routers

To remove the files from a compact Flash memory card previously formatted with a Class B Flash filesystem, perform one of these procedures:

	For external compact Flash memory cards, issue the erase slot0: command.
	For internal compact Flash memory cards, issue the erase flash: command.

To format an external compact Flash memory card with a Class B Flash filesystem, refer to this sample output:

Router# erase slot0:

Erasing the slot0 filesystem will remove all files! Continue? [confirm]
Current DOS File System flash card in slot0: will be formatted into Low
End File System flash card! Continue? [confirm]
Erasing device...
eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
eeeeeeeeeeeeeeeeee
...erased
Erase of slot0: complete

To remove the files from a compact Flash memory card previously formatted with a Class A or Class C Flash filesystem, perform one of these procedures:

	For external compact Flash memory cards, issue the format slot0: command.
	For internal compact Flash memory cards, issue the format flash: command.

To format an internal compact Flash memory card with a Class A or Class C Flash filesystem, refer to this sample output:

Router# format flash:

Format operation may take a while. Continue? [confirm]
Format operation will destroy all data in "flash:". Continue? [confirm]
Enter volume ID (up to 64 chars)[default flash]:
Current Low End File System flash card in flash will be formatted into DOS
File System flash card! Continue? [confirm]
Format:Drive communication & 1st Sector Write OK...
Writing Monlib sectors ............................
Monlib write complete
..
Format:All system sectors written. OK...

Format:Total sectors in formatted partition:250592
Format:Total bytes in formatted partition:128303104
Format:Operation completed successfully.

Format of flash complete

For more information you may wish to refer to:

Cisco PCMCIA Filesystem Compatibility Matrix and Filesystem Information

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• Cisco
• LANs / WANs
• SMB
• AS5800 Dial Shelf Controller (DSC)
• default flash
• erase command
• erase flash: command
• erase slot0: command
• format command
• format flash: command
• format slot0: command
• squeeze command