HTC Desire Phone Storage != Physical size On my Android HTC Desire, it says that I have 5.30 GB of phone storage, whilst my physical size is 8 GB. The 5.30 GB of phone storage seems to be composed of 4.52 GB available, 776 MB of apps, and a few other bits.

Why does the phone storage not equal the physical size? Is this because the remaining memory is taken up by operating system files which I am not allowed to access, or something else? If anyone can confirm the composition of this seemingly extra memory and post links to resources on this, that would be highly appreciated.

Note Android version 4.4.2. Model number = HTC_Desire_320
That is because your phone has several partitions, and some of those are not user-accessible, but they are required by the OS for the proper functioning of the device. This storage is "partitioned" from your physical storage. These partitions are as follows:

1) bootloader or variants thereof: About a few MB. Responsible for booting up your device. You can't normally mess with it, even with root on-device, but even if you can, you shouldn't.

2) /boot: Contains the OS core, the Linux kernel. About 10-25 MB, varies with device.

3) /recovery: The name is pretty self-explanatory. About 10-25 MB. Responsible for doing OTA updates, factory resets and saving your device when it gets into a bootloop. Most rooted users usually flash a custom recovery like CWM or TWRP before going forward with customization.

4) /system: About 1-1.5GB, varies with device. Stores system data and apps. Read-only to normal users, write-capable for root. Most root users mess with this partition on a regular basis.

5) /data: About 1GB- depending on device. On devices with unified storage, this partition holds the internal SD card too as an emulated device. It is not even read-only to normal users, but it can be written to and read with root. It holds user-installed apps, their data, and user-specific data.

6) /cache: App and data cache. From 16-256 MB. A kind of temporary storage provided to apps.

Note: A factory data reset wipes /data and /cache only.

7) radio or variants thereof: A few MB. Again, responsible for handling telephony. Don't mess with this.

8) /storage/sdcard0: On non-unified storage devices, this is the user-available storage as a separate partition. On unified storage devices, this is still there, but is a folder under /data actually, with write permissions for normal users, unlike the rest of /data.

For any more info, a Google search will help. Or you can check this out.

Also, the partition names are the ones I got from fastboot while flashing my HTC Nexus 9 (16GB,WiFi, flounder/volantis) when upgrading Android via factory images.