Sample Dump Standard (SDS)
The 1986 MIDI protocol for moving audio samples between samplers and computers, one patient byte at a time.
The MIDI Manufacturers Association adopted SDS in 1986, and it is built entirely on SysEx. A header describes bit depth, sample rate and loop points; the audio follows in packets carrying 120 bytes of payload, each with its own checksum. The receiver answers ACK, or NAK to request a resend, so a flaky cable doesn't ruin the transfer.
The bottleneck is bandwidth. MIDI runs at 31.25 kbit/s and each data byte can only carry seven bits, so a few hundred kilobytes of sample data take several minutes. That was tolerable when a sampler had 512 KB of memory. Once SCSI, floppies and later USB sticks became normal, almost everyone stopped bothering — but the protocol is still in the spec and in plenty of vintage gear.