Example use of pyparted to achieve partition alignments with non-devices that the parted command cannot.

pyparted-test.py

#!/usr/bin/env python

import parted

def add_partition(disk, free, align=None, length=None, fs_type=None, type=parted.PARTITION_NORMAL):
    start = free.start
    if length:
        end = start + length - 1
    else:
        end = free.end
        length = free.end - start + 1

    if not align:
        align = disk.partitionAlignment.intersect(disk.device.optimumAlignment)

    if not align.isAligned(free, start):
        start = align.alignNearest(free, start)

    end_align = parted.Alignment(offset=align.offset - 1, grainSize=align.grainSize)
    if not end_align.isAligned(free, end):
        end = end_align.alignNearest(free, end)

    geometry = parted.Geometry(disk.device, start=start, end=end)
    if fs_type:
        fs = parted.FileSystem(type=fs_type, geometry=geometry)
    else:
        fs = None
    partition = parted.Partition(disk, type=type, geometry=geometry, fs=fs)
    constraint = parted.Constraint(exactGeom=partition.geometry)
    disk.addPartition(partition, constraint)
    return partition

def get_free_regions(disk, align):
    """Get a filtered list of free regions, excluding the gaps due to partition alignment"""
    regions = disk.getFreeSpaceRegions()
    new_regions = []
    for region in regions:
        if region.length > align.grainSize:
            new_regions.append(region)
    return new_regions

def kib_to_sectors(device, kib):
    return parted.sizeToSectors(kib, 'KiB', device.sectorSize)


boot_size = 144584 * 512
align = parted.Alignment(offset=63, grainSize=63*255)

device = parted.Device("./foo")
disk = parted.freshDisk(device, "msdos")

boot_partition = add_partition(disk, get_free_regions(disk, align)[0], align, boot_size / 512, fs_type='fat32')
boot_partition.setFlag(parted.PARTITION_BOOT)

root_partition = add_partition(disk, get_free_regions(disk, align)[0])

disk.commit()