---
title: IOStorage
framework: kernel
role: symbol
role_heading: Class
path: kernel/iostorage
---

# IOStorage

The common base class for mass storage objects.

## Declaration

```occ
class IOStorage : IOService
```

## Overview

Overview The IOStorage class is the common base class for mass storage objects. It is an abstract class that defines the open/close/read/write APIs that need to be implemented in a given subclass. Synchronous versions of the read/write APIs are provided here -- they are coded in such a way as to wrap the asynchronous versions implemented in the subclass.

## Topics

### Miscellaneous

- [complete](kernel/iostorage/1810767-complete.md)
- [copyPhysicalExtent](kernel/iostorage/1810820-copyphysicalextent.md)
- [handleClose](kernel/iostorage/1810866-handleclose.md)
- [handleIsOpen](kernel/iostorage/1810905-handleisopen.md)
- [handleOpen](kernel/iostorage/1810948-handleopen.md)
- [lockPhysicalExtents](kernel/iostorage/1810985-lockphysicalextents.md)
- [open](kernel/iostorage/1811013-open.md)
- [read()](kernel/iostorage/1811038-read.md)
- [read()](kernel/iostorage/1811068-read.md)
- [synchronizeCache](kernel/iostorage/1811091-synchronizecache.md)
- [unlockPhysicalExtents](kernel/iostorage/1811117-unlockphysicalextents.md)
- [unmap](kernel/iostorage/1811145-unmap.md)
- [write()](kernel/iostorage/1811168-write.md)
- [write()](kernel/iostorage/1811185-write.md)

### Instance Methods

- [attach](kernel/iostorage/1574956-attach.md)
- [copyPhysicalExtent](kernel/iostorage/1574993-copyphysicalextent.md)
- [discard](kernel/iostorage/1574961-discard.md)
- [getMetaClass](kernel/iostorage/1574982-getmetaclass.md)
- [getProvisionStatus](kernel/iostorage/1644751-getprovisionstatus.md)
- [handleClose](kernel/iostorage/1574998-handleclose.md)
- [handleIsOpen](kernel/iostorage/1574986-handleisopen.md)
- [handleOpen](kernel/iostorage/1574957-handleopen.md)
- [lockPhysicalExtents](kernel/iostorage/1575002-lockphysicalextents.md)
- [open](kernel/iostorage/1574976-open.md)
- [read](kernel/iostorage/1574962-read.md)
- [read](kernel/iostorage/3516780-read.md)
- [setPriority](kernel/iostorage/1574967-setpriority.md)
- [synchronize](kernel/iostorage/1574954-synchronize.md)
- [synchronizeCache](kernel/iostorage/1574981-synchronizecache.md)
- [unlockPhysicalExtents](kernel/iostorage/1574979-unlockphysicalextents.md)
- [unmap](kernel/iostorage/1575001-unmap.md)
- [write](kernel/iostorage/1574965-write.md)
- [write](kernel/iostorage/3516781-write.md)

### Type Methods

- [complete](kernel/iostorage/1575005-complete.md)

## Relationships

### Inherits From

- [IOService](kernel/ioservice.md)

## See Also

### Drivers

- [IOBDBlockStorageDriver](kernel/iobdblockstoragedriver.md)
- [IODVDBlockStorageDriver](kernel/iodvdblockstoragedriver.md)
- [IOCDBlockStorageDriver](kernel/iocdblockstoragedriver.md)
- [IOBlockStorageDriver](kernel/ioblockstoragedriver.md)