Dear All -
If I use the command fdisk -l I get the usual and expected output of the style
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 131604479 131602432 62.8G 7 HPFS/NTFS/exFAT
/dev/sda2 131604480 1180327679 1048723200 500.1G 7 HPFS/NTFS/exFAT
/dev/sda3 1180327680 2229050879 1048723200 500.1G 7 HPFS/NTFS/exFAT
My question concerns the line
/dev/sda1 * 2048 131604479 131602432 62.8G 7 HPFS/NTFS/exFAT
Surely that means that /dev/sda1 starts at sector number 2048 and that there are 2,048 sectors at the start of /dev/sda (yes, numbered 0000-2047) allocated otherwise?
For various reasons I want to zero these initial sectors of /dev/sda using the command
dd if=/dev/zero of=/dev/sda count=2048
but to my annoyance (and very considerable damage to the system) this also zeroes the first sector of /dev/sda1.
That is, the dd command zeroes not just those sectors numbered 0000-2047 but also the sector numbered 2048: so 2049 altogether. not 2048.
I am absolutely convinced that my understanding of counts / numbers / numbering as described above was correct under 7.4.2 and that I issued commands, many times, in the manner describe without damaging /dev/sda1; (but I am a bit nervous now about checking that)!
Can anybody conform that I am right? That I am wrong? That dd under 8.2.0 is glitchy?
Thank you!
Fergus
PS And by the way (completely different and unconnected) I find the file /boot/isolinux/ifcpu64.c32 is broken in the 8.2.0 installation and I have to over-write it with the same file from 7.4.2 for things to work properly. Anybody else?
Fergus

Dell PowerEdge R730XD 28 Core Server 2X Xeon E5-2680 V4 H730 32GB RAM No HDD
$378.93
Dell EMC PowerEdge R440 Xeon silver 4215 2.5GHz 16 GB ram 2x 550W PSU No HDD
$275.00
Dell Poweredge R630 2x Xeon E5-2680 v3 2.5ghz 24-Cores / 64gb / Raid / 2x 1Tb
$374.99
Dell PowerEdge R240 Intel Xeon E-2224 3.50GHz 8GB DDR4 ECC NO HDD 250W
$285.97
Dell Poweredge R810 4x Xeon X7560 2.26ghz 32-Cores | 256GB | 3x Trays | H700
$289.99
Dell Poweredge R630 2x Xeon E5-2680 v3 2.5ghz 24-Core | HBA330 | No RAM or HDD
$149.99
Dell Poweredge R630 2x Intel Xeon E5-2650 v4 64GB RAM No Drives/OS Server
$441.00
Dell PowerEdge R640 10SFF 2x Gold 6140 2.3GHz 36-Cores 64gb H730p 2x Trays
$599.99
Dell PowerEdge R530 2x E5-2630v4 H330 iDRAC8 Port Card Riser No PSU/RAM/HDD
$99.99
Dell Poweredge R630 2x Xeon E5-2680 v3 2.5ghz 24-Cores | 32gb | HBA330 | 2x 1...
$324.99