The earlier Quantums (pre-1990) were somewhat noisy, slow, and unreliable. Apple used these in most SE/30s (some examples from 1991 may have a newer drive). These were also common in most Macs aside from the 20MB SE until the ProDrive LPS and ELS came about. I remember hearing about Apple drives being unreliable back when these were fairly current. Quantums became more dependable in the early 1990s but the long term reliability, of course, seems to be a toss-up based on what everyone has written here so far.
It was also common to pull a drive from an LC in the late 1990s and stick it inside another Mac. Many recommended this about ten years ago when LCs were common and inexpensive/free on the used market, especially because the drives were better performers than anything the SE/30s, SEs, and some Mac IIs contained.
I only have two pre-1990 Quantums--a 40MB and a 105MB. (Only the 40MB is Apple-branded). I've had a few die on me, and most have been 80MB in capacity. Of course, there could be extraneous factors here too (namely the former life of an SE/30 or Mac II as a server). Additionally, it could be that a Mac originally had a 40MB or 80MB and someone replaced it with a larger drive.
Most Apple-branded ProDrive LPS/EPS seem to have a ©1990 EPROM sticker on them. I think they were this way until sometime in 1993. The ProDrives were also common as non-Apple drives, and any older LaCie unit will contain a Quantum, as LaCie used to have corporate relations with Quantum (a manual from a drive I got in 1993 says "LaCie: A Quantum Company" on its cover).
It was also common to pull a drive from an LC in the late 1990s and stick it inside another Mac. Many recommended this about ten years ago when LCs were common and inexpensive/free on the used market, especially because the drives were better performers than anything the SE/30s, SEs, and some Mac IIs contained.
I only have two pre-1990 Quantums--a 40MB and a 105MB. (Only the 40MB is Apple-branded). I've had a few die on me, and most have been 80MB in capacity. Of course, there could be extraneous factors here too (namely the former life of an SE/30 or Mac II as a server). Additionally, it could be that a Mac originally had a 40MB or 80MB and someone replaced it with a larger drive.
Most Apple-branded ProDrive LPS/EPS seem to have a ©1990 EPROM sticker on them. I think they were this way until sometime in 1993. The ProDrives were also common as non-Apple drives, and any older LaCie unit will contain a Quantum, as LaCie used to have corporate relations with Quantum (a manual from a drive I got in 1993 says "LaCie: A Quantum Company" on its cover).