SEAGATE TECHNOLOGY, INC. Customer Technical Support FAX Network +1 408 438-8137 Customer Technical Support Bulletin Boards (300-9600, 8-N-1) /----------------------------------+---------------------------------\ | United States +1 408 438-8771 | United Kingdom +44 628 478011 | +----------------------------------+---------------------------------| | Germany +49 89 140-9331 | Singapore +65 227-2217 | \----------------------------------+---------------------------------/ (C)opyright 1991 ST-3550N Rear View /- 50 pin SCSI Interface I/O connector | | DC power (TOP) #============ ===========# /-5-G-G-12\ ====#::::::::::::::::::::::::1#=# 0 0 0 0 #= (BOTTOM) \=========================/ \---------/ /-----1 /-----1 /-----1 \-----/ \-----/ \-----/ Terminating Resistor Packs ST-3550N Left View o o o1 (TOP) o o o #=# Front....==================#=#=#=====# I/O connector | | | \=/ SCSI Address ID 1 -/ | | ID 2 ---/ | ID 4 -----/ ST-3550N Right View o o4 o o o6 (TOP) #=# 1o|o 1o|o o DC Power #====#====== | ================================ \=/ | | | --+---- | Active/Passive Termination --+-- --+---- Terminator Power /---+----------------------------\ --+-- | Active: Pins 1 & 2 shorted | | | only (+2.85V to | | | 110 ê) for FAST | | | SCSI; | | |Passive: Pins 2 & 4 shorted | | | AND pins 5 & 6 shorted | | | (+5V and GND to | | | 220/330 ê) for | | | standard SCSI. | | \--------------------------------/ | /-------------+--------------------------------------------------------\ |Terminator Power: From SCSI Connector ---------------- Pins 1 & 2 | | From Power Connector --------------- Pins 1 & 3 | | To SCSI Connector Only ------------- Pins 3 & 4 | | From Power Connector and ----------- Pins 1 & 2 AND | | to SCSI Bus --------------------------- 3 & 4 | | Terminating Resistors not Installed - Pins 2 & 4 | \----------------------------------------------------------------------/ ST-3550N Front View /------------------ SCSI ID's (none for ID0) | not used if ID set on side jumpers | /-------------- Ext. Spindle Clock Synch | | pin-5 is Clock Ground | | /------------ Remote LED (TOP) /-+-\ | | /------ Reserved 4 2 1 | | /---+---\ o o o o o-o o o o o 1o o o o o+o o o o o o o o o+ ====================1o o o o-================ | | | | (BOTTOM) | | | \-- Remote LED | | \---- Ext. Spindle Clock Synch | | pin-5 is Clock Ground | \------ Remote Start Enable \-------- Parity Enable ST-3550N UNFORMATTED CAPACITY _____________________ FORMATTED CAPACITY (xx SECTORS) __________456.5 AVERAGE SECTORS PER TRACK ________________83 rounded down ACTUATOR TYPE ____________________________ROTARY VOICE COIL TRACKS ___________________________________10,630 CYLINDERS ________________________________2,126 (user) HEADS ____________________________________5 DISCS (3.5 in) ___________________________3 MEDIA TYPE _______________________________THIN FILM HEAD TYPE ________________________________THIN FILM RECORDING METHOD _________________________ZBR RLL (1,7) INTERNAL TRANSFER RATE (mbits/sec) _______21.6 to 36.3 EXTERNAL TRANSFER RATE (mbyte/sec) _______4 Async EXTERNAL TRANSFER RATE (mbyte/sec) _______10 Sync SPINDLE SPEED (RPM) ______________________4,500 AVERAGE LATENCY (mSEC) ___________________6.67 BUFFER ___________________________________256 Kbyte SeaCache Multisegmented, read look-ahead INTERFACE ________________________________SCSI-2 Fast BYTES PER TRACK __________________________42,943 avg. SECTORS PER DRIVE ________________________891,574 TPI (TRACKS PER INCH) ____________________2,400 BPI (BITS PER INCH) ______________________52,602 AVERAGE ACCESS (ms) ______________________12 SINGLE TRACK SEEK (ms) ___________________<4 MAX FULL SEEK (ms) _______________________32 MTBF (power-on hours) Office _____________250,000 POWER REQUIREMENTS: +12V START-UP (amps) _1.9 POWER MANAGEMENT (Watts): ACTIVE _______________5.75 IDLE _________________3.0 STANDBY ______________1.0 WRITE PRECOMP (cyl) ______________________N/A REDUCED WRITE CURRENT (cyl) ______________N/A LANDING ZONE (cyl) _______________________AUTO IBM AT DRIVE TYPE ________________________0 Formatted at the factory with 2 alternate cylinders. Total physical cylinders equal 2128. Physical: Height (inches/mm): 1.00/25.4 Width (inches/mm): 4.02/102.1 Depth (inches/mm): 5.77/146.6 Weight (lbs/kg): 1.5/0.68 Note: If FAST SCSI transfer rates are used, then the active termination options must be used. If the transfer rates are 5.0 MBytes/sec and below, either method of termination can be used. Although active and passive terminated devices can be installed on the same bus, both ends of the cable should be terminated in the same manner, either both active or both passive. Note: If your application requires no terminators, remove the terminators from the circuit board. Merely removing the terminator power source selection jumper does not disconnect the terminator resistors from the circuit. ZBR = Zone Bit Recording = Variable sectors per track Seagate reserves the right to change, without notice, product offerings or specifications. (08/08/94)