HDAT2 vs Piston
HDAT2
hdat2.comPiston
piston.appSide by side
| Figure | HDAT2 | Piston |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | — |
| Android | — | Yes |
| Plans published | 1 | 2 |
| Spec score · Hardware Diagnostic Software | 7.7 (#8) | 7.2 (#19) |
| Purpose | HDAT2 tests and diagnoses ATA, ATAPI, SATA, NVMe, SSD and SCSI/USB devices. | Piston turns an Android mobile device into a car scanner for reading diagnostic trouble codes and Freeze Frame data. |
Plans
In their own words
HDAT2
HDAT2 is a drive-testing and diagnostic program for ATA, ATAPI, SATA, NVMe, SSD, and SCSI/USB devices. Its device-level tools test drives and can repair bad sectors on detected devices. File-system testing covers MBR/GPT, boot data, and directories on FAT12/16/32, exFAT, and NTFS. SMART functions are available for ATA/SATA, SCSI, and NVMe drives. Capacity controls include SET MAX and Device Configuration Overlay, with options to restore full capacity; supported SATA and NVMe devices can also be switched between 512e logical sectors and 4Kn. HDAT2 detects devices on AHCI and some RAID controllers, and USB devices through USB ASPI or BIOS when supported. The main program requires a real DOS system booted from USB, floppy disk, or CD/DVD. A Windows 32/64-bit demo is available, but it operates only at drive level, omits file-level functions, and aborts almost all commands while simulating conflicts. The freeware plan is free, for one or more machines, with redistribution without profit; it is provided as-is without warranty.
Piston
Piston is an Android app that turns a phone into a scanner for vehicle diagnostics. It works with OBD-II and EOBD vehicles through a separate ELM327 adapter connected by Bluetooth or WiFi. The free plan costs nothing and includes reading and clearing diagnostic trouble codes, viewing Freeze Frame data, and reading real-time sensor data. Access is limited to information the vehicle provides through OBD2. Premium adds sensor charts, CSV export, Readiness Monitors, fault history, cloud sync, and VIN reading. Some older vehicles may not support VIN readout. Piston uses Firebase services for crash reporting, monitoring, analytics, authentication, remote configuration, and cloud storage. Settings provide opt-outs for several data services, and account deletion permanently removes associated data.