Ensoniq SQ-80 Disk Format The disk contains data on both sides with 80 tracks numbered 0 - 79 on each side. However, each track has five 1024 byte sectors numbered consecutively from zero to four followed by one sector of 512 bytes with a sector ID of five. I will refer to the two sides of the disk by referring to the disk drive head used to read each side. The heads are numbered 0 and 1. Data is stored on both sides of each track before moving to the next track. However, when switching tracks, the system remains on the same head as the previous track. The following examples should clarify this. TK HD SC 0 0 0-5 data is first stored on Track 0, Head 0, Sectors 0-5 0 1 0-5 data is next stored on Track 0, Head 1, Sectors 0-5 1 1 0-5 data is then stored on Track 1, Head 1, Sectors 0-5 1 0 0-5 data is then stored on Track 1, Head 0, Sectors 0-5 2 0 0-5 data is then stored on Track 2, Head 0, Sectors 0-5 this process continues until.... 79 0 0-5 the last track - Track 79, Head 0, Sectors 0-5 (Track 79, Head 1, Sectors 0-5 were written first) SQ-80 Sector Information Finding your way around an SQ-80 diskette is not an easy task. Some of the files (and the directory) are stored on the smaller sectors, while others are stored on both! All files on the SQ-80 are stored in fixed locations eliminating the need for a file allocation table. The format allows for ten (10) large data files (any combination of one-sequence, all-sequence, or system-exclusive files). Each file occupies 64 contiguous large sectors (sectors 0-4) of the diskette. In addition, each of the ten files occupies one small sector (sector 5) located on the same track and head as the last large sector. (Simply set the sector number to five after reading the last large sector). This small sector is only used to store header information for the all-sequence files. It is not used for the other two types. The format also allows for 40 program bank files. These files occupy four large sectors each starting at Track 64, using the remaining large sectors on the diskette. The diskette direc- tory occupies the first four small sectors of the diskette as shown below. The remaining small sectors are used to store the 128 individual programs (sounds) with each program occupying one sector. However, the program files are not on alternating sides. The first 64 are stored on head 0, and the last 64 are stored on head 1. The ten program locations which conflict with the small sectors occupied by the large data files are stored in the small sectors starting at Track 66, Head 0, Sector 5. (I'm not making this up - this is really the way it works!) TK HD SC 0 0 5 Directory (First Sector) 0 1 5 Directory (Second Sector) 1 1 5 Directory (Third Sector) 1 0 5 Directory (Last Sector) 2 0 5 Program # 1 3 0 5 Program # 2 4 0 5 Program # 3 5 0 5 Program # 4 7 0 5 Program # 6 (Program # 5 stored at 66,0,5) 8 0 5 Program # 7 Continues until.... 65 0 5 Program # 64 2 1 5 Program # 65 3 1 5 Program # 66 Continues until.... 65 1 5 Program # 128 0 0 0 Large Data File # 1 (First Sector) 6 0 3 Large Data File # 1 (Last Sector) 6 0 4 Large Data File # 2 (First Sector) 6 0 5 Large Data File # 1 (Small Sector) 12 1 2 Large Data File # 2 (Last Sector) 12 1 3 Large Data File # 3 (First Sector) 12 1 5 Large Data File # 2 (Small Sector) 19 1 1 Large Data File # 3 (Last Sector) 19 1 2 Large Data File # 4 (First Sector) 19 1 5 Large Data File # 3 (Small Sector) 25 0 0 Large Data File # 4 (Last Sector) 25 0 1 Large Data File # 5 (First Sector) 25 0 5 Large Data File # 4 (Small Sector) 31 0 4 Large Data File # 5 (Last Sector) 31 0 5 Large Data File # 5 (Small Sector) 32 0 0 Large Data File # 6 (First Sector) 38 0 3 Large Data File # 6 (Last Sector) 38 0 4 Large Data File # 7 (First Sector) 38 0 5 Large Data File # 6 (Small Sector) 44 1 2 Large Data File # 7 (Last Sector) 44 1 3 Large Data File # 8 (First Sector) 44 1 5 Large Data File # 7 (Small Sector) 51 1 1 Large Data File # 8 (Last Sector) 51 1 2 Large Data File # 9 (First Sector) 51 1 5 Large Data File # 8 (Small Sector) 57 0 0 Large Data File # 9 (Last Sector) 57 0 1 Large Data File #10 (First Sector) 57 0 5 Large Data File # 9 (Small Sector) 63 0 4 Large Data File #10 (Last Sector) 63 0 5 Large Data File #10 (Small Sector) 64 0 0 Program Bank # 1 (Sector 1 of 4) 64 1 0 Program Bank # 2 (Sector 1 of 4) 65 1 0 Program Bank # 3 (Sector 1 of 4) 65 0 0 Program Bank # 4 (Sector 1 of 4) Continues until .... 79 0 0 Program Bank # 40 (Sector 1 of 4) Ensoniq SQ-80 Directory Sectors The SQ-80 does NOT use its directory for the 128 individual programs stored on the disk. These files are stored in a fixed location on the disk and must be read directly to obtain the names of the sounds. Banks of sounds and the ten 64K files are listed in the regular directory but the position of the directory entries is fixed. This eliminates the need for a file allocation table since the files are in fixed locations. The first 10 entries are for the ten large data (64K) files for sequences, all sequences, and system exclusive files. The next 40 entries in the directory are for the 40 bank files. Ensoniq SQ-80 Directory Entries Each Entry contains 13 bytes of data. Byte Information 01 File Type - see list of types 02-11 File Name (10 Bytes) 12 Type-dependant Information 13 Type-dependant Information The SQ-80 File Names can contain some unusual characters since the keyboard used some non-ACSII characters. See Joe Slater's article (Issue #70, page 13) to find out the meaning of these characters. In fact, Joe's entire series of articles on the ESQ-1 are valid for the SQ-80 as well. Ensoniq SQ-80 File Types 00 (00) = Unused (Blank) 01 (01) = Operating System 02 (02) = Program Bank File 03 (03) = All Sequence File 04 (04) = One Sequence File 05 (05) = System Exclusive File 06 (06) = Single Program File -- Gary Giebler