Do I have an SSD and a hard drive on my MacBook Pro?

Question

I looked at the details provided in my system report/storage and I noticed that it appears I have a hard drive of 499.05GB and an additional SSD drive of 499.42GB. Does this mean I have 1TB of data? I only have 139GB available so do I have 500GB 'hiding' somewhere? (If so where??) I am unsure how to interpret this information- why does it list both storage types? Is it duplicating the information?

Macintosh HD:

Available: 139.8 GB (139,800,666,112 bytes)
Capacity: 499.05 GB (499,046,809,600 bytes)
Mount Point: /
File System: Journaled HFS+ Writable: Yes
Ignore Ownership: No
BSD Name: disk1
Volume UUID: EF0908C8-XXXX-XXXX-XXXX-XXXX80333709

Logical Volume: Revertible: Yes (unlock and decryption required)
Encrypted: Yes
Encryption Type: AES-XTS
Locked: No
LV UUID: 8CC9C88D-XXXX-XXXX-XXXX-XXXX2002329B

Logical Volume Group:
Name: Macintosh HD Size: 499.42 GB (499,418,034,176 bytes)
Free Space: 18.9 MB (18,903,040 bytes)
LVG UUID: EE040070-XXXX-XXXX-XXXX-XXXXA83B309

Physical Volumes:

disk0s2: #is this a second disk?

Device Name: APPLE SSD SM0512G
Media Name: APPLE SSD SM0512G
Media Size: 499.42 GB (499,418,034,176 bytes)
Medium Type: SSD
Protocol: PCI
Internal: Yes
Partition Map Type: GPT(GUID Partition Table) #does this mean its partitioned?
Status: Online
S.M.A.R.T. Status: Verified
PV UUID: A1391405-XXXX-XXXX-XXXX-XXX2E8FCDF3

Answer 1

If you consider SSDs being hard drives then you have an SSD and a hard drive on your MBP. It's still only one device with ~500 GB disk space.

The main partition of your SSD is encrypted with FileVault2. While enabling FV2 the main partition is transformed to CoreStorage which is an LVM - an additional layer between physical disk and file system. The resulting Logical Volume is shown as an additional disk in Disk Utility/diskutil info.

A common partition layout looks like this:

disk0 (500.1 GB) → disk0s1 (209.7 MB) EFI
                 ↘︎ disk0s2 (499.4 GB) Macintosh HD
                 ↘︎ disk0s3 (650.0 MB) Recovery HD

disk0s2 (Macintosh HD) is mounted to root (/)

After converting the disk to CoreStorage, disk0s2 is converted to a Physical Volume which sets up a Logical Volume Group. The existing file system on disk0s2 is shrunk a bit, converted to a Logical Volume and encrypted:

disk0 (500.1 GB) → disk0s1 (209.7 MB) EFI
                 ↘︎ disk0s2 (499.4 GB) LVG/PV → disk1    (499.05 GB) LV/Macintosh HD
                                             ↘︎ metadata (~370 MB)
                 ↘︎ disk0s3 (650.0 MB) Recovery HD

Now disk1 (~disk0s2) is mounted to root (/).

So disk1 is almost congruent to disk0s2 (except some 100 MB at the end of disk0s2 which is used for metadata and isn't encrypted).

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CoreStorage is not limited to encrypt volumes as FileVault2 "container". Every regular volume can be converted to a CS LVG/PV/LV. Apple uses it to create Fusion Drives and SSDs are usually partitioned/formatted as CoreStorage volumes.