4 ms·

So... what's the Cortex used for?

• MrBuddyCasino 12y ago
  You mean the extra M3 core I guess? I wondered too, but I suspect it was just part of the vendor's chip design and went unused - if they could have saved some money by not including it, they probably would.
• lovelearning 12y ago
  I'm just speculating here, but Cortex-M series are known for their DSP capabilities. DSP is used in hard drive control. From wikipedia [1], "Typically a DSP in the electronics inside the hard drive takes the raw analog voltages from the read head and uses PRML and Reed–Solomon error correction to decode the sector boundaries and sector data, then sends that data out the standard interface. That DSP also watches the error rate detected by error detection and correction, and performs bad sector remapping, data collection for Self-Monitoring, Analysis, and Reporting Technology, and other internal tasks." And one of the comments on the blog[2] mentions "...whereas the Cortex's ID turns up relevant boundary scan file..." [1]: http://en.wikipedia.org/wiki/Hard_disk_drive_interface http://en.wikipedia.org/wiki/Hard_disk_drive_interface [2]: http://spritesmods.com/?art=hddhack&page=8&showall=true http://spritesmods.com/?art=hddhack&page=8&showall=true
  • TheLoneWolfling 12y ago
    He mentioned that disabling it didn't seem to do anything, however. ("The Cortex-M3 handles... nothing? I could stop it and still have all hard disk functions.") So SMART and bad sector remapping, perhaps. But not decoding.
• magila 12y ago
  Probably nothing. Creating the masks needed to mass produce chips is expensive so manufacturers will often use the same chip for multiple products. The M3 may be used by higher end products (i.e. enterprise drives) or it may just be the vestigial leftovers of some feature which was planned but didn't ship.