# Understanding Storage Gateway Resources and Resource IDs
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In Storage Gateway, the primary resource is a *gateway* but other resource types include: *volume*, * virtual tape*, *iSCSI target*, and *vtl device*. These are referred to as *subresources* and they don't exist unless they are associated with a gateway.

These resources and subresources have unique Amazon Resource Names (ARNs) associated with them as shown in the following table.


| Resource Type | ARN Format | 
| --- | --- | 
| Gateway ARN | `arn:aws:storagegateway:{{region}}:{{account-id}}:gateway/{{gateway-id}}` | 
| Tape ARN | `arn:aws:storagegateway:{{region}}:{{account-id}}:tape/{{tapebarcode}}` | 
| Target ARN ( iSCSI target) | `arn:aws:storagegateway:{{region}}:{{account-id}}:gateway/{{gateway-id}}/target/{{iSCSItarget}}` | 
|  VTL Device ARN  | `arn:aws:storagegateway:{{region}}:{{account-id}}:gateway/{{gateway-id}}/device/{{vtldevice}}` | 

Storage Gateway also supports the use of EC2 instances and EBS volumes and snapshots. These resources are Amazon EC2 resources that are used in Storage Gateway.

## Working with Resource IDs
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When you create a resource, Storage Gateway assigns the resource a unique resource ID. This resource ID is part of the resource ARN. A resource ID takes the form of a resource identifier, followed by a hyphen, and a unique combination of eight letters and numbers. For example, a gateway ID is of the form `sgw-12A3456B` where `sgw` is the resource identifier for gateways.

For virtual tapes, you can prepend a up to a four character prefix to the barcode ID to help you organize your tapes.