Here is a list of IDE drives known to either work or not work with Acorn hardware. If the drive appears with no notes then it will work fine with the machine specified. Many thanks to those who have contributed their info.
Manufacturer Part Number Size Interface Notes Quantum Sirocco 2560 Std/RiscPC New Filecore Seagate 2150 Std/RiscPC IBM Aquarius 2148 Std/RiscPC WstnDigtl Caviar 2148 Std/RiscPC  Samsung WA32163A 2062 Simtec IDE IBM DJAA-31700 1740 Std/RiscPC Quantum SR1700AT 1740 Std/RiscPC NEC DSE1700A 1700 Std/RiscPC M-CDU76E S-CFS210A WestDig WD31600 1638 ICS (FS 3.13) (Partition on old filecore) Quantum FB1280AT 1310 Std/RiscPC M-ToshibaXM5302B CDROM S-CFS420A Conner CFS1275A 1275 Std/RiscPC M-CFS425 S-CFS420A S-CFS210A Seagate ST51270A 1223 Std/RiscPC M-CFS425 M-SonyCDU6ECDR Fujitsu M160TAU 1089 Std/RiscPC Wont master. Quantum Fireball 1080 ICS/RiscPC Quantum Fireball 1024 Std/RiscPC Seagate 31220A 1024 ICS/RiscPC Master only Seagate ST580A 850 Std/RiscPC Conner CFS850A 850 ICS (FS 3.12) M-M2684TAM  Samsung SHD-30560A 560 Std/RiscPC M-CP3204F S-QMav540A WstrnDigtl Caviar 2540 540 Std/RiscPC <DOESN'T WORK> E-IDE WstrnDigtl WD2540H 540 Std/RiscPC Conner CFA540A 540  Quantum 540 DT Soft Format to 512M Fujitsu 1603T 540 Std/A5000 RPC Format 1023cyls = 503Mb space Quantum Maverick 540A 540 Std/RiscPC M-CP3204F M-SHD30560A Conner CFS540A 540 Std/RiscPC Formats to 512M Conner CFS541A 540 Std/A5000 M-CP30104H EIDE (512M = 1039 cyls) Fujitsu M2684TAM 528 ICS Real 504M S-H3171-A2  IBM DSAA-3540 528 Std/RiscPC Odd noises!  Seagate ST5660A 528 Std/RiscPC Format to 512M (1039 Cycls) Quantum LPS540A 504 Std/RiscPC Fujitsu M2684TAM 504 ICS (FS 3.13) S-ST9145AG Conner CFS425A 425 Std/AnyAcorn Doesn't link to CFS210A and CFS425A WstrnDigtl Caviar 420 Std/RiscPC  Conner CFS420A 420 Std/Acorn Evolution # M-CP3044 M-CFS210A M-FB1280AT Seagate 420 ICS Maxtor 7420AV 420 ICS Conner CP30424 (?) 420 ICS Seagate ST3491A 408  Maxtor 7345A 340 Std/RiscPC S-CFS210. Wont work alone Fujitsu M286T 340 Watford M-S-NEC D3756 Seagate ST3389A 335 Std/RPC Evolution/A5000 Quantum Prodrive 270 HCCS/A440 RPC Seagate ST9300AG 260 Watford S-CFS420A 2.5 drive Conner CP30254 250 ICS M-CP3044 S-CFS420A WstrnDigtl 250 ICS Seagate ST3290A 250 A310 Conner CFN250A 240 HCCSUltimate/A3010 Conner CFS210A 210 Std/RiscPC # S-CFS420A Conner CP3204F 210 Std/RiscPC S-QMav540A Conner CP3204F 210 Evolution WstrnDigtl Caviar 200 Std/AnyAcorn WILL NOT WORK (poss ) IBM H3171-A2 171 ICS M-M2984TAM Real 163MB Conner CP30174E 170 Std/A5000 SyQuest EX135i 135 Std/RiscPC700 Maxtor 7120 130 ICS Disable on-disc cache. (ICS util) Seagate ST3144A 120 A310 Quantum LPS127A 120 ICS Castle 120 Castle/A3000 Conner CP30104H 116 Std/A5000 S-CP540A SyQuest SQ3105 AT 105 Std/A5000 M-CP3044 S-CFS420A NEC D3756 100 Watford M-S-M286T Rodime RO3139AP 100 Watford Works alone wont co-exist. Maxtor 7080 85 ICS Disable on-disc cache. (ICS util) Conner CP3085 (?) 85 ICS Running off computer's PSU too! Conner CF3008E 80 Std/A5000 A4000 # Maxtor 80 ICS (FS 2.03) Conner CP30084E 80 Std/A5000 M-S-CP3044 Use links on base not drive face. Seagate ST51A/X 40 Std/RiscPC S-CFS420A Seagate ST351A/X 40 Watford IDE Conner CP3044 40 Std/A5000 # S-SQ3105 AT PrairieTek 20 ICS (FS 2.01) NEC CDR-273 CDROM Std/RiscPC600 Aztech CDROM Std/RiscPC700 NEC CDR-273 4x CDROM Std/RiscPC NEC CDR-1300A 6x CDROM Std/RiscPC NEC CDR1400A 8x CDROM Std/RiscPC BTC BCD 739 8X CDROM Std/RiscPC Wont in Risc OS, will on PC-Card... Phillips PCA53 5x CDROM Std/RiscPC Wont in Risc OS, will on PC-Card... Creatv Labs Hex-Speed CDROM Std/RiscPC
Enlargements to notes:
 Formatted to 3 partitions 248M 248M & 316M (to get small LFAU)
 Seagate ST3491A Wont S/M to CFS240A (High end A5000). Will slave to CFS420A (Risc PC)
 This drive recalibrates for thermal adjustments every 10mins, making a click.
 CFA drives will work with RISC OS 3.60 (new Risc PCs, A7000) but not with older versions of the Acorn IDE interface. They will work on ICS interfaces though. (Badly defined part of IDE spec aparently)
 The HCCS interface apparently doesn't like podule slot 0, but is happy in others.
 WD Caviars often have initialisation problems - there is a fix elsewhere in the FAQ for this.
Understanding the list:
Disclaimer: This list reports the reported experiences of others. Neither the maintainer, nor the contributors are definitely saying that these combinations will work - just that they have for them. So don't sue us!
DRIVE AS SOLE AS MASTER AS SLAVE HSP C/D DSP ACT HSP C/D DSP ACT HSP C/D DSP ACT CP3044 - y - y - y y y - - - y CP3008E - y - - - y - - - - - - CP30126 - y - - - y y - - - - - CP30174E - y - - - y - - - - - - CFS210A - y - - - y - - - - - - CFS420A - y - - - y - - - - - -
Link connectors are on the front of the drive, the narrower end that doesn't have the cables coming in, next to the activity light connector (which is missing on Risc PC Drives - it's on the motherboard)
It should also be noted that if you need an extra linker don't expect it to have been provided (notably on the CF3008E, the 80M drive in the A4000 & A5000.)
(Details translated from table by Dave Walker, as published in Acorn User Sept 95. Not all permutations have been tested)
Extra submissions welcome!